Should I insulate the floor of the attic of the sloped sides of the roof? I also have dampness issues. The house is under insulated and is also drafty.

A: It sounds like you have two different problems: insulation and moisture. You need to deal with both. My fundamental question is where is the moisture coming from? The usual culprit is the basement. If the basement is damp (in summer when the humidity is high dampness in the basement is usually caused by warm moist air condensing on the cooler surfaces (especially cold-water pipes) and in the winter it is caused by water wicking up from the ground. This, in turn is often caused by leaking guttering and downspouts that dump the water right by the basement wall. Leaking pipes cause dampness year round. 
First, fix the source of the dampness. So get downspout extenders and clean out the clogged leaves in the gutters and maybe fit perforated plates on top of the gutter, and fill any cracks in the basement wall with exterior grade spray foam. I did this on my rental property and it greatly helped. Then I would seriously consider replacing your hot water tank (I am assuming it is heated from your furnace) with a heat pump hot-water tank. A Rheem 55 gallon hybrid heat pump hot water tank at Home Depot costs about $1200, you can get a $600 rebate on this. It will take an hour or two with an electrician and plumber to install it. These heat your water at less than the cost of heating oil and about the same as heating with natural gas. However they also dehumidify your basement and that is the big plus. Ideally you would also insulate the ceiling of your basement (just push fiberglass in between the rafters or ask MassSaver to do it for you) to prevent the heat from your house just leaking down into the basement and becoming the source of heat for your heat pump hot water tank. This is a good fix for you but if you also get solar panels you would be saving a ton of money on heating your hot water, even if you are on natural gas today. 
With the moisture dealt with, I think it would be fine to insulate the attic  either on the floor or the sloped sides of the roof. Which you do depends mostly on whether you use the attic as storage space. If you do, the sloped side is better. If ever you intend in the future to install a heat pump for heating the house with an air-handler unit in the attic you MUST insulate the sloped part of the roof or you will get icicles and ice dams in winter. You could either wait a season to see if the moisture fixes work or insulate the slopes with fiberglass or Rockwool because they are permeable to air and so will allow a small amount of condensation to evaporate. The best solution is to add a one-way vapor permeable membrane (but 100% air tight) on the inside of the rafters/insulation such as Intello which you can get from Building 475 in Connecticut. You need a pro to install this and I have consulted with Dolphin but I have not hired them yet because I need to deal with the water issues in my basement first! This membrane prevents moisture traveling from the loft to the roof surface but still allows any moisture from behind the membrane to evaporate to the inside. This insulation-plus-Intello-approach is about the gold standard in roof design and I am about to use it on my other rental property. This is going to be more expensive than just blowing in cellulose to the floor of the attic, but it will still save you loads of money on the bills and give you a completely air tight roof and get rid of the condensation problems in the attic. However, still fix the source of moisture first, because that moisture is causing mold elsewhere in the house, condensation on windows and probably even making the towels stay damp on the rack too.

Net Metering and the Cost of Heat Pumps and Solar Panels in New Hampshire.

Q1. Sustainability of Net Metering

I asked a question about the longevity of the net metering program and Lori framed it as somewhat of a political question. I was trying to ask a question more about energy markets and energy storage. If enough people get solar, the supply of solar electricity at the time of production may exceed the demand. As far as I know, there is no cost effective way to store this excess energy on a large scale. Without storage, the excess energy becomes worthless and as you said, the financials of the net metering program will fall apart. 

Here’s a link to one article:
I suppose my questions would be: do you know of any data that suggest a time line for the decrease in value of solar energy? I guess most importantly would be whether the net metering program will change before the pay back period of the system (say 10 years for talking purposes). Or maybe there’s data that say even if there are solar panels on every roof, the production will still not exceed the daytime energy demand, in which case the net metering program can be considered more or less safe. 

A1: I think there are two questions here: the first is for how long is net metering (as currently practiced in MA) sustainable and the second is can excess solar power be cost-effectively stored at grid scale?

The economics of net metering are very unfavorable to the utility company. By law they are forced to buy solar electricity from homeowners at the full retail price (in MA about 23c/kWh) when they can buy it from a power station at about 8c/kWh. This is a subsidy from all ratepayers to those ratepayers who have solar panels. This can only work as long as the amount of solar power subject to net metering is small compared to the total amount of electricity being consumed. This is true today but is becoming less so as more solar power is installed on rooftops and more commercial-scale solar panel farms are being constructed to supply community-sourced solar power as an option to ratepayers. Eventually the utilities will seek to negotiate less favorable terms for net metering. This is a negotiation with the government and hence things will move slowly. I do not expect net-metering to go away, probably ever, but I do expect to see its generosity to the homeowner decrease over time. The net-metering credit rate is already cut back to 60% of the retail value for arrays over 10kW in size. It also already excludes some taxes and fees and  it excludes the monthly fixed charge of $7 per month. In other states net metering is already far less generous than it is in MA. Of all the subsides for solar panels in MA, the federal tax credit, the state SMART subsidy and the net-metering subsidy, net metering is the biggest of all three. 
On the second question about can excess solar electricity be cost-effectively stored at grid scale the answer is yes. Both California and Australia have installed very large batteries to store excess electricity. In MA, Eversource (our utility company) is doing something similar by paying homeowners to have access to their home-based back-up batteries during times of peak demand on the grid. The program is called Connected Solutions and it seems to be quite generous. I have recently placed orders for two new solar panel arrays each with batteries to replace broken propane back-up generators. When a battery is installed with fairly large solar panel arrays (over about 10kW) the combination now pays for itself in seven or eight years. 

Q2. Heat Pump Efficiency

I asked a question about estimating the required electricity to run heat pumps and your answer was to calculate the heat energy contained in the oil I burned this winter (in kWh) and divide by 2.5. This makes sense to me since a 2.5 COP corresponds to a heat pump HSPF of 8.5, which I believe is fairly standard. I’m a little confused by the section of your book where you talk about heat pumps having 400% efficiency, or COP=4. Is this a theoretical value that maybe does not account for the electricity required to run the fans? Or is this based on a very efficient heat pump with HSPF=13.6?

A: In the book I do refer to heat pumps being 400% or 4x as efficient as a furnace. This is true for a heat-pump hot-water heater and a heat pump for heating a swimming pool. When I wrote the book I thought it was also true for heat pumps for heating the air in a house. However, since writing the book, research has been published by well-regarded scientists that shows that the year-round average COP in New England is about 2.5. In the webinar I now use 2.5, not 4.0. When I measured the real, year-round COP on my two houses the one with the Bosch heat pumps has a COP of about 3.0 and the one with the Mitsubishi heat pumps has a COP of about 2.5. This is very similar to what was found by the academic researchers i.e., that ducted systems were more efficient than ductless systems and that Bosch was more efficient that Mitsubishi. These numbers include the electricity to run the fans as well as the compressor.

Q: Along the same lines, you talk about how it only makes sense to heat using heat pumps if you have cheap solar electricity. However, if utility electricity in MA is 23c/kWh, doesn’t that mean you’re making heat with heat pumps for 23/2.5=9.2c/kWh, making it only slightly more expensive than heating oil (6-7c/kWh)? 

I agree with you that the cost of heating the house is 23c/2.5 = 9.2c/kWh of heat in the house. Heating with heating oil (which contains about 40kWh of heat per gallon) at $2.59 a gallon (what I am currently paying) with an 85% efficient furnace (better than my dinosaur furnace) means that heat in the house costs about 8c/kWh. So paying 9.2c/kWh of heat in the house by using heat pump on utility electricity is about 15% more expensive than heating with oil. If you can achieve a COP of 3.0 (as I do with my Bosch ducted heat pumps) then the cost of heating the house is almost exactly the same as heating with heating oil. For me it was actually a saving because my dinosaur furnace is only about 75% efficient. However, even if the running cost is the same, you have to buy a new heat pump whereas you already have an existing furnace. This is why I recommend you install heat pumps when your AC units fail not when your furnace fails. Replacing a broken AC unit with a heat pump is about 40% more expensive than replacing it with a new AC unit. But now you get heating and cooling. However, leave the old furnace in place so you have a back-up heating system should the heat pump not be able to heat the house in very cold weather and so you have a heating system during grid outages. Note that you will still need either a back-up generator or a battery so that you can run the pumps and fans on electricity during the grid outage. If you don’t do this you will have a hot furnace and a cold house. 

3. Solar Financial Feasibility
I am having some trouble getting the financials of solar to make sense. I am using the numbers you  provided in your book as a general measuring stick (ie the array should produce at under 10c/kWh, and you have seen quotes down around 5c/kWh). I am in NH, and it seems one of the huge differences between MA and NH is in how SRECs are handled. I spoke with an installer today who said the current value of an SREC is NH is $5. Over 25 years, this adds up to about $1200, which stands in stark contrast to the $29000 in your book. (I have read a few articles about how the program is broken in NH because utilities are allowed to collect unclaimed SRECs for free, which depresses their value). Without this benefit, it looks impossible to me to get the solar electricity cost down to 1/3 of the utility cost, which is around what you quoted in the book. 

The value of an SREC in MA is currently about $250/MWh so it is very different to NH!

Q: Here are some numbers, which are roughly accurate. I just received a quote for a 11.1kW system for $27000 (after the federal income tax credit). Production over 25 years is around 238,000 kWh, which works out to be 11c/kWh. 

Current utility rates from NHEC are around 15c/kWh and the net meter rate is around 10c/kWh. Assuming the system produces enough power that there are always net meter credits to work with, the cost of power when the system is overproducing is just the system cost (11c/kWh) and the cost of power in the winter when the system is underproducing is the system cost plus the difference between the utility rate and the net meter rate (11+(15-10) = 16c/kWh). When using heat pumps, a large % of annual power consumption happens in the winter. As far as I understand it, this power actually costs 1c/kWh more than the standard utility rate. But maybe this really doesn’t matter since, as discussed above, if I’m using a heat pump with COP=2.5, then the cost of heat is 16/2.5=6.4c/kWh, which is basically the same as oil. One of the points you make in the book is that the cost of solar electricity is fixed. However, if you are using a lot of electricity through the net metering process, you still have to buy this electricity at the utility rate. 

A: NH has much lower utility rates than MA. This is in part driven by all the subsidy schemes like full-retail-price net metering, SMART and Connected Solutions which drive up the price of electricity for all the MA ratepayers who are not taking advantage of the subsidies. So you are getting a net-metering credit of 10c/kWh on the excess solar electricity you produce in summer but are paying 15c/kWh in winter when the heat pumps are used the most. This suggests a slightly different version of the Fab Four recipe for you. I would invest much more in lowering the energy use of your house such as great insulation, air-sealing and upgrading you windows. Then, when your AC units fail, replace them with heat pumps and add solar panels if it is cost-effective, which it may not be. With such cheap electricity, you may be better off financially using a heat pump (after insulation and air sealing) and replacing your gasoline vehicles with EVs rather than getting solar panels.

Q: My conclusion here is that without significant SREC value in NH, there is no way for me to push the cost of solar low enough to be a great investment when compared to other investment opportunities (granted, I haven’t done a detailed financial evaluation yet). On the plus side, I don’t think I will lose money here, and it obviously still makes tremendous sense in terms of cutting carbon. Would you agree with this conclusion? Or would you consider cheaper solar panels (ie not LG, Sunpower, or Panasonic) here to try to improve the economics (I have received a quote using REC panels that is closer to 8c/kWh)?

A: REC makes a great panel – I almost bought it until my installer decided to quit installing batteries, since I wanted a battery I had to get a new installer. The new installer gave me a better deal on Solaria panels at about 6c/kWh including a battery. At 8c/kWh and COP 3.0 you would be heating the house at 2.7c/kWh of heat in the house which is 1/3 of the cost of heating with heating oil and about half the cost of heating with natural gas. This is roughly the situation at my house. I heat with a heat pump, cook on induction, run a heat-pump hot-water tank and drive my Tesla, all charged with the cheap electricity from my solar panels. All with a zero carbon footprint.

Designing the pool to be efficient from the start

Q: We currently have a Hayward H250 natural gas heater on our 16’ X 28’ In ground pool and have thought about replacing it with a heat pump. Several years ago I installed a 2 speed pump on the pool and we now save a lot of kilowatts by using the lower speed. However when we want to heat the water we must run the pump on high speed to meet the gas heaters minimum pressure requirement. It’s not really much of a problem because we only use the pool from mid May till mid September and with the solar cover on it holds the heat in pretty good unless we have some unusually cool weather. We also have what I call an indirect solar heating system on the pool that adds a little extra heat as well so we don’t have to run the gas heater very much once we get the water up to temperature. As such I was wondering if the heat pump pool water heater that you use requires you to run your pool pump on high speed to keep your water warm? 

My indirect solar pool heating system consists of 400’ of polybutylene tubing that I put in the concrete that surrounds the pool. I feed it with pool water coming off a tee fitting that I installed after the filter but before the heater. Of course I have a ball valve installed so that I can shut it off at night. Once the water exits the 400’ of tubing that is buried in the concrete it just gravity flows back into the pool. I can send you som photos of it if you’re interested in learning more about it. Another benefit of using this indirect solar system or maybe we should call it a reverse radiant system is that it keeps the concrete a little cooler on those very hot sunny days. My grandkids really appreciate that.

A: This sounds like a well thought out installation – I like the passive pool heater which heats the water and cools the deck, a very nice two-for! I think this would work on most pool decks, but obviously you need to do this from the start. If I were designing a pool from the start I would also connect the pool heat-pump heater to the house AC system, but that is a different subject, you can read more about it here if you like:
Our pool heat pump is made by AquaCal and it has proven to be both reliable and efficient. When we installed it, we left the old propane heater in place but we no longer use it at all. If it did not cost me money to take it out, I would have taken it out by now. 
The heat-pump pool heater does have a minimum water-flow requirement to work and on our pool and it is at about 1,400 rpm on the variable-speed pump motor for the water-circulating pump. I usually set the water pump at 2,000 rpm so that it circulates the entire pool volume once per 24 hours, which is necessary to keep the pool water filtered. So it is usually enough flow to allow the heater to come on. However, if the skimmers and filter are clogged, the heat pump will shut down because the water flow is insufficient even at 2,000 rpm.  
The pool-water circulating pump now runs 24/7 at 2,000 rpm compared to the old fixed-speed motor that ran at 3,450 rpm about 12 hours a day. This alone is saving me about 75% of the electricity used to run the pool. If you already have a 2-speed motor it is probably not going to save you a lot more money to go with a variable-speed motor. But when you need to replace the pump, I would recommend a variable-speed one as then you can set it to the lowest flow rate needed to circulate the entire pool volume in 24 hours. There is a lot more information on how we got to a zero-carbon footprint on our pool in the book Zero Carbon Pool which you can order here:

Free AC in my house from heat pump heaters for swimming pools and heat-pump hot -water tanks

Q: I haven’t yet read your pool topic & wonder if you’ve seen the pool heater that uses waste central AC heat?

A: You are well ahead of the pack on your thinking on swimming-pool heaters. My pool heater is a standard issue AquaCal heat pump – it is very good and very economical to run. On warm days when we are heating the pool, (say a warm day in May) it exhausts cool dehumidified air into the atmosphere, truly global cooling! My pool is too far from my house to capture this and use it as AC in the house. But if ever built a house with a pool I would design it so that the heat pump for the pool would dump its cool air into the house. Free AC! I do not know of any heat pumps designed to do this but it would be fairly easy (i.e., you would need to hire an HVAC tech to do it) to run the refrigerant line from the heat pump to the head of a mini-split unit in the house. If you do this, please let me know, I would very much like to publicize stories like this. 

While I have not done this on my pool I have done something similar on my house. I do this by opening the vents (where the air filters slot in) in my air-handler units in my house in about May through September. This is when it is warm enough outdoors that I need AC indoors. Rather than turning on the AC, I open the vents on the air handlers in the basement. This draws air out of the basement and into the circulation of the house. I lean the filter pads against the open vent so that the air circulation is still filtered. The air in my basement is cool and dry. Why? My heat-pump hot-water tank cools and dehumidifies the air in the basement. This works because the ceiling of the basement is very well insulated at approx. R38 because I added 12” of fiberglass in between the floor joists. Using this source of cool, dry air allows me to avoid using the AC units for about 4 weeks in the year when previously I had to use them.  It is not a major cost saving but it is a nice one. I like anything I can get for free! If houses were properly designed, things like this and the integration of pool heating with house cooling, would be built in from the start. Sadly these people seem to not talk to each other. 

If you are seriously thinking of putting in a pool then the $15 you spend on Zero Carbon Pool could be one of the best investments you will ever make. I am saving about $3,000 a year. My pool is big, but even on a standard sized 20’x40’ pool you would save about $1,000 a year by following the pool fab four recipe. 

Combination solar PV and solar thermal panels for swimming pools

Q:  Are you aware of solar panel company called FaFco they make a combination solar panel PV / Thermal….. The thermal output is about 10,000 BTU per 10 FT. SQ. These are making an impact in the swimming pool industry. Have you looked at these FAFCO .?

A: I have not heard of this panel, but it does not overcome the biggest issue with solar thermal panels which is that you cannot store the heat generated on a sunny day and use it on a cloudy day. With solar PV you can effectively store the energy because of net metering. However, using them to heat pool water is a better idea than using them to heat a house. I would have to check the economics compared to just installing solar PV and using it to power a heat-pump hot-water heater for the pool.

Q&A From High-School Students after seeing my webinar for homework:

Out of all of the jobs you have had, which has been your favorite, and why?My career was in biotechnology, not energy. We produced a new product that combined stem cells from the patient with a tube made from plastic nanofibers to replace the trachea or esophagus of a patient with something awful like throat cancer. My favorite moment was being in the operating room, dressed in surgical scrubs, with the first patient in the US, a baby girl, who was born without a trachea.
I’m aware of when you got this idea, but when you were getting your two degrees did you know that you wanted to enter into the environmental realm?No, not at all. My career in biotechnology combined science and business so it built on both of my degrees.
What made you first begin to capture data and really invest your time into making these changes in your home, as well as your lifestyle?Two things. First my kids were interested in it and second, I had to take time off work to recuperate from a nasty road accident. That was what gave me the time to do the research.
How feasible of an option is solar given that our area of the country doesn’t get as much sun as areas like Arizona or New Mexico? Is it more difficult to have more solar panels installed onto houses without flat roofs?Solar panels work in MA, many homes have them. It is sunnier in AZ but the subsidies from the state government are better in MA. Houses with south facing sloped roofs generate about 10% more electricity per square foot than a flat roof. Sloped roofs that face east or west generate about the same electricity per square foot as a flat roof.
Are there severe detriments to your solar panels because of the snow/New England weather?No, the snow just melts off within a few days.
You mentioned in the video that you bought a Tesla earlier in 2020, and that the cost per mile dropped to only 2 cents per mile. What might be a more cost-friendly option to teens and/or people who are looking to cut down on their carbon footprint related to transportation that can’t afford the up front cost of a Tesla?Leasing a car is a good option if you do not have the up-front cash.
Do you think the reason why people don’t change to a more environmentally friendly lifestyle is because it is too much money economically?This used to be the case, but today it is more that people do not know they can save money by cutting their carbon footprint, which is why I frequently do webinars to educate people that you can. The webinars are very effective – 72% of webinar attendees say they intend to install at least one of the fab four within a year.
What was the biggest hardship that you and your team had to overcome during your process to produce a zero carbon home?We have big windows in our house that look out over a large grassy area that attracts deer and even coyotes. My whole family was concerned that low-E triple glazed windows would look green and hence distort our wonderful views. I ordered sample panels of several different types of low E glass in double and triple-glazed glass and set them up on our deck so that everyone could see them before we bought them. The first round of samples all arrived broken so it was a very long and involved process before we decided on the final windows. We chose ones that were very clear and transparent on the ground floor and ones that were slightly tinted green on the upper floor. Now they are installed no-one thinks they have even the slightest green tint – but convincing everyone took a lot of work!
What is the hardest part/most difficult change to transitioning to a zero carbon footprint?Installing the windows was a very long process. By contrast the heat pumps, insulation and solar panels were fairly quick.
What are some ideas you have for ways to convince people that being carbon neutral is an economically advantageous decision as opposed to more expensive than they are willing to pay when there is such a strong narrative out there that it is incredibly expensive?I do the webinar for free 2-3 times a month and give the book away free to all attendees.
These savings seem incredible to me, so I’m wondering why this knowledge isn’t more widespread. I have never seen advertisements for any of these things.I honestly think I am the first person to do both the financial analysis and the energy savings analysis with such a scientific approach. I wrote the book precisely because there was no guide book. I would have been very happy to use someone else’s guidebook, but there was none.
How long would it take to accomplish a zero carbon home/footprint (timeline to implement the fab four start to finish)?It took about 2.5 years from start to finish. But this was because I was doing everything for the first time. With homeowners who I advise on how to save money by cutting their carbon footprint it takes about a year.
Do zero carbon homes require lots of maintenance to keep the solar panels and other components performing well?No.
Do you in any way feel that, by your neighbors seeing what you’ve done for your home and how much money it is saving you each year, that they may follow in your footsteps?I am encouraging them to do so!
Why are geothermal pumps more costly than air pumps?It is mostly the cost of drilling the wells. The heat pump itself is about the same cost as an air-sourced heat pump.
What made you study finance but shift gears in your focus of your studies to environmental science and applications like these?I spent 25 year in biotechnology. It was only after the road accident that I focused on cutting our carbon footprint.
What is it like seeing your work referenced on a national stage?It is always nice to get recognition like that, but I honestly feel better when a homeowner tells me about how much money they are saving because of installing one or more of the fab four.
What are your thoughts on windmills for people who have large fields in towns like dover and sherborn.I looked into a wind turbine at our home. But with trees around it is not viable.
What do the Rs represent in the grade of insulation? Are you able to get an insulation that is higher quality than R50?R comes from resistance, as in resistance to heat flowing. You can always get more R value by increasing the thickness of the insulation. However, more than R50 is probably not worth it. 
What would you say to someone if they still don’t want to switch to the fab four? How could you convince them further?I have found that wanting to save money is almost universal. If even that does not get people interested I find the health aspects like reducing the risk of asthma for a family member is often a good way to spark interest.
Does the fab four also work for schools and other community buildings are does it have to be modified?Yes. The fab four recipe is rooted in the laws of physics and those are the same everywhere. The subsidies are a little different for commercial properties, schools and homes but the basic recipe is the same.
Our winters can get bitterly cold, sometimes below zero for long periods of time. Can your heat pumps support a large home in this scenario?No. In my experience heat pumps cannot keep a house at 70F when the temperature outside is below about 20F which happens on about 20 days a year in New England. This is why I always recommend that you keep your old furnace as a back-up heating system.
Do you think Britain is better at cutting down carbon emissions than the US?Britain has done a very good job of closing coal-fired power stations and building offshore wind farms. The US is usually ahead of Europe in all things technological (how many European internet companies can you name?), but in this area, especially wind farms, Europe is far ahead of the US.
My house is Surrounded by lots of trees and doesn’t receive much sunlight. Are there any alternatives to solar that are just as beneficial.You can get your electricity from a community solar installation. There are several companies offering this in MA. Their electricity is 100% solar, usually from large arrays in rural areas. They sell you the electricity, usually at 10% off the utility rate and one offers 12.5% off.
There seems to be a focus on heating, what is the contrast with cooling? Is the fab 4 solution still the best?In MA, winter heating costs far more (and has a far higher carbon footprint) than summer cooling. This is why I focus on heating.  In the winter you want to keep the heat in. In the summer you want to keep the heat out. The answer is the same in both cases – insulation, draft-sealing and triple-glazed windows.
Living in a house that doesn’t seem very sustainable and is far from zero carbon, what is the best place to start moving toward a zero carbon home? Even with bringing awareness to the idea/ the first stepsAlmost always the best place to start is with insulation and draft sealing. MassSave will pay for almost all of it. Go to their website and book a no-cost, virtual audit.
I would like to know more about the benefits of a carbon neutral home when you are only a few years away from selling it. My parents like the idea of solar panels but say its too late to get them.According to Zillow, houses with solar panels sell for about 4% more than comparable houses without solar panels. Academic studies show that houses with heat pumps sell for between 4-7% more than comparable houses without heat pumps. These price increases often exceed the cost of adding the solar panels and heat pumps. Hence, adding them is a good way to position your house for selling it and you will probably get more money out of the sale than you invested in the fab four.
How can I save money and cut down on my carbon footprint while living in a dorm while going to college? What techniques can I use while living in a dorm. (obviously I won’t be able to install solar panels or triple glass windows ect.)In a dorm room there are still things you can do: block drafts under doors and around windows; make your own “fit from the inside” triple glazed windows (I have done this) using a simple wood frame and the stretchy plastic film you can buy at any hardware store, and advocate for solar panels. The recipe for the windows is in the book, “Special COVID-19 Edition of Zero Carbon Home” which you can download for free from my website or it that does not work send me an email to and I will email you the pdf file.
Is there a way to use the fab four if you live in a smaller residence like an apartment or a condo since it might be harder to use solar panels?Yes. Focus on insulation, draft sealing and window inserts. Also see if your condo association is interested in putting solar panels on the roof.
Do you think it’s going to take people a long time to realize that going zero is one of the best things for the environment and actually try to do so? Or do you think there will be a rapid response with the new generations?I am trying my hardest to make it happen fast!
How do you recommend we spread word of the fab four?Talk to your parents over dinner. Say things like, “Did you know you can save a lot of money on heating bills by cutting your carbon footprint? We studied it in class today. Someone in Dover, you won’t believe this, his name is Mr. Green, he has cut his house’s carbon footprint to zero and he pays nothing for heating or electricity. He does webinars on it. Can we watch the next one together?” Sign up for the free webinar on my website, all attendees get a free copy of my book Zero Carbon Home too.
Can you elaborate on the ways tax breaks and subsidies contribute to the success of the fab 4?There is a lot here. I cover the subsidies for each of the fab four in the book. But, in short, MassSave will pay for insulation and draft sealing. Solar panels are heavily subsidized by the federal government, the MA government and your utility company. Heat pumps are subsidized by your electric utility and with the 0% interest Heat Loan from Masssave. Triple-glazed windows can also be subsidized with the Heat Loan.
Do you think it is possible for people to have their own windmills instead of solar panels?Yes, but it is far more expensive than solar panels.
How can we as teenagers do this… it’s not always an easy transition for adults/homeownersTalk to your parents over dinner. Say things like, “Did you know you can save a lot of money on heating bills by cutting your carbon footprint? We studied it in class today. Someone in Dover, you won’t believe this, his name is Mr. Green, he has cut his house’s carbon footprint to zero and he pays nothing for heating or electricity. He does webinars on it. Can we watch the next one together?”
How long do solar panels last and do they become less effective over time?The power output is guaranteed by the manufacturer for 25 years and they will probably produce electricity for 40 years. They become about 10% less efficient after 25 years.
What was your role as a strategy consultant?I advised large companies on how to improve their competitiveness. I also worked in South Africa in 94/95 which was when apartheid gave way to democracy and I advise the new government, headed by Nelson Mandela, with its industrial strategy.
What led you to be studying this? When did you realize this was your passion?The scientist in me has always been interested in energy. As a kid, I was fascinated by the potential of making hydrogen and oxygen from water with electricity. So, I have always been passionate about science and spent 25 years in biotechnology. I only got interested in zero carbon stuff when I was doing it on my own house. When I realised that I had cut the carbon footprint of my house to zero, which no-one thought possible, and I was saving so much money on heating and electricity bills that I was making a very good return on my investment, I decided I needed to spread the word and wrote the books.
How many members of our community have gone carbon neutral? What else are you doing to spread this amazing message?My sister, who lives in England, is interested and my sister-in-law, who lives in Needham, has added heat pumps and solar panels. I personaly know of at least 12 people who have cut their carbon footprint by using the fab four after seeing one of my webinars, and if the 72% of webinar attendees who say they will add at least one of the fab four in the next year actually do so, then over 1,300 homes will have done something major to cut their carbon footprint. 
Around how long will it take for you to make back the money spent on the fab four from cheaper heating?About 6 years.
If people only wanted to or could afford to use 1 or 2 components of the Fab Four, would it still be worth it and effective even though they’re not completely zero?Yes. It is not necessary for everyone to get to zero. One homeowner I know cut his carbon footprint 38% with just insulation, draft sealing and home-made triple-glazed windows. He spent $1,000. You do not need to go zero. Do what is right for your family. But do it.
How should we, as non-homeowners, contribute to lowering our carbon emissions?Talk to your parents over dinner. Say things like, “Did you know you can save a lot of money on heating bills by cutting your carbon footprint? We studied it in class today. Someone in Dover, you won’t believe this, his name is Mr. Green, he has cut his house’s carbon footprint to zero and he pays nothing for heating or electricity. He does webinars on it. Can we watch the next one together?”
What is a piece of advice you have for others who want to find innovative / entrepreneurial ways to help the environment?Whether you become a scientist or not, I believe a strong grasp of the fundamentals of science (such as gathering the data, carefully observing the real world, doing experiments and analyzing the results) will give you a strong ability to be both innovative and entrepreneurial. 
Do they offer Triple- Glazed Windows at hardware stores such as Home Depot?Probably not. I got all my triple-glazed windows directly from the manufacturers. 

Green Hydrogen and the Hydrogen Economy. Q: I keep on asking the questions but no one gives me an answer:-The are three grades of hydrogen:
Grey (high levels of CO2), Blue (low levels of CO2) and green (no CO2) 
Based on what I have read so far the Grey and Blue are made from natural gas while the Green is made from breaking down water.
There is also a maximum amount of hydrogen that can be piped though regular old fashioned gas pipes.

My big question is “How much does Blue hydrogen cost above natural gas?”

A: I do not know the answer but you are asking the right question. 
Energy is a total commodity, only the lowest cost player (or fuel) will survive. This is why coal displaced wood for heating homes, then natural gas displaced coal. Natural gas is now displacing oil for both heating and electricity generation. Now solar and wind are starting to displace natural gas for heating (solar PV plus a heat pump is half the cost to heat your home than natural gas) and for transport (solar PV plus a Tesla costs 2c per mile vs. gasoline at 10c per mile). It is game over for fossil fuels. Unfortunately it will take 20 years. But the outcome is now inevitable.

I doubt that even green hydrogen will be low enough cost to be able to compete with renewables and heat pumps for heating or renewables and electric vehicles for transport. 

The only way to make green hydrogen today is to use solar or wind electricity to split water molecules into hydrogen and oxygen. This is fundamentally less efficient (i.e., more expensive) that just using the renewable electricity directly. There may be some niche applications, such as using excess solar electricity (that would otherwise be wasted) during sunny days to make hydrogen and then burning the hydrogen at night to run a power plant. But other than temporary energy storage, I just do not see hydrogen being competitive with solar, heat pumps and EVs.

Q: You mentioned that you  have an EV.  Do you find it performs well when it gets really cold?  Are charging stations easy to find, or do you mostly charge at home?  

Yes we have an EV, I bought a Tesla model S about a year ago. We have three kids and they are all taller than my wife so we needed a car big enough for 5 adults. Also, I wanted 4WD given the winters we have in NE. This made the model S about the only option. We bought the long range 100kWh battery and that gives it a range of about 400 miles. The performance in really cold weather (like this week) has been completely normal except that the mileage goes down. If I drove it today it might only get 250 miles on a full charge. Unless the weather is really cold the range stays at about 400 miles.
It is charged about once a week from home (we had an electrician install a Tesla wall charger which charges much faster than just plugging it into a 110V socket) almost always overnight. When we do long trips (like the 400 miles round trip to NYC and back) we stop and recharge at a Tesla supercharger station which can add about 200 miles of range in about 20 minutes. There are many supercharger stations and the car’s software tells you which ones have spaces free and directs you to them. They are usually just off the highway in a shopping mall or something similar. So road trips are not a worry, in fact taking a break every 3 hours or so is actually quite convenient. 

Q: Will electric vehicle play an important role in zero carbon emission?

A: Yes. According to a study at MIT authored by Prof. Jessica Trancik, the lifetime cost of owning an EV (which means the cost to buy it, plus the cost to repair and maintain it plus the cost of fuel) is now at or below that of owning a gasoline-powered vehicle. Her study assumed that you were paying utility rates for electricity. If you are using cheap solar power from your roof the lifetime cost of an EV is now lower than that of a gasoline-powered vehicle. If you power your EV from your solar panels then your transportation with have a zero-carbon footprint too and emit no pollution.

My wife recently drove in our Tesla to New York City and back in a day, a distance of about 400 miles. The whole trip cost $8. And had a zero-carbon footprint. The Greyhound costs $26, the seats are uncomfortable and it drops you at the Port Authority Bus Terminal.