Zero Carbon ® Blog

The Powerpoint document, which you can download below is a draft of proposed legislation intended to cut the carbon dioxide emissions from MA homes to net zero by 2050. It builds on my book, my webinar and my work advising homeowners on how to cut their carbon emissions in the most cost-effective way possible. In my consulting work I have never failed to cut a homeowner’s utility bills and carbon emissions substantially, and sometimes to zero.

It gets the average home to net zero by adding insulation, heat pumps and solar panels to almost all 2 million homes in MA. By taking advantage of the generous subsides from both the MA government (net metering, MassSave rebates and tax credits) and the federal government (rebates and tax credits under the Inflation Reduction Act or IRA) you can reduce the upfront cost of a heat pump by between 80-100%, reduce the cost of insulation by up to 100% and reduce the cost of solar panels more than 30%. Any balance can be financed with either zero-interest-rate-loans from MassSave (up to 7 years and up to $25,000) or low-interest-rate-loans (maximum 2%) from the Massachusetts Community Climate Bank , or MCCB, (up to 20 years and up to $100,000).

Adding heat pumps (while retaining the existing fossil-fuel heater as a back up), insulation and solar panels to the average 1,800sf home in MA will cut the bills for heating and electricity by $208 per month or $2,500 a year. Even assuming that the net cost is financed at the highest interest rate on the MCCB loan (2%), the net monthly saving (after the loan servicing costs) is $111 per month or $1,332 per year. According to large-scale, independent, academic research, this cut in bills will increase the home price by about $50,000. Plus the house has a brand-new heating system. If the house already has AC, it now has a brand new AC system. If the house does not have AC, it now has it for the first time. Not bad really. I expect these huge benefits to the homeowner to lead to at least a tripling of requests for a MassSave audit and subsequent installation of insulation, heat pumps and solar. A tripling of the number of houses retrofitted under the MassSave program each year from the current 25,000 to 75,000 means that all 2 million MA homes are retrofitted by 2050.

If you have any comments, questions or criticism of this plan please email me at [email protected]

The Word document, which you can download below is a draft of proposed legislation intended to cut the carbon dioxide emissions from MA homes to net zero by 2050. It builds on my book, my webinar and my work advising homeowners on how to cut their carbon emissions in the most cost-effective way possible. In my consulting work I have never failed to cut a homeowner’s utility bills and carbon emissions substantially, and sometimes to zero.

It gets the average home to net zero by adding insulation, heat pumps and solar panels to almost all 2 million homes in MA. By taking advantage of the generous subsides from both the MA government (net metering, MassSave rebates and tax credits) and the federal government (rebates and tax credits under the Inflation Reduction Act or IRA) you can reduce the upfront cost of a heat pump by between 80-100%, reduce the cost of insulation by up to 100% and reduce the cost of solar panels more than 30%. Any balance can be financed with either zero-interest-rate-loans from MassSave (up to 7 years and up to $25,000) or low-interest-rate-loans (maximum 2%) from the Massachusetts Community Climate Bank , or MCCB, (up to 20 years and up to $100,000).

Adding heat pumps (while retaining the existing fossil-fuel heater as a back up), insulation and solar panels to the average 1,800sf home in MA will cut the bills for heating and electricity by $208 per month or $2,500 a year. Even assuming that the net cost is financed at the highest interest rate on the MCCB loan (2%), the net monthly saving (after the loan servicing costs) is $111 per month or $1,332 per year. According to large-scale, independent, academic research, this cut in bills will increase the home price by about $50,000. Plus the house has a brand-new heating system. If the house already has AC, it now has a brand new AC system. If the house does not have AC, it now has it for the first time. Not bad really. I expect these huge benefits to the homeowner to lead to at least a tripling of requests for a MassSave audit and subsequent installation of insulation, heat pumps and solar. A tripling of the number of houses retrofitted under the MassSave program each year from the current 25,000 to 75,000 means that all 2 million MA homes are retrofitted by 2050.

If you have any comments, questions or criticism of this plan please email me at [email protected]

Today I got another check from the government, see attached. $7,500 from MA for buying an EV (my Ford F150 Lightning truck). I get another $7,500 from the Federal Government on April 15th.  The Pro version of the F150 Lightning (I have the Lariat version which is longer range) lists for $49k. It gets the same $15k off. That’s $34k net. You can’t get a better car for such little money. I ran my house from the Ford during the recent grid outage, see pic. I no longer need an unreliable, expensive and polluting back-up generator.

David Green – the “Green Guru”

The highly-acclaimed book “Zero Carbon Home”

How we cut our home’s carbon emissions to zero

Useful links:

The Easiest Way to Calculate Your Home’s Carbon Footprint:https://greenzerocarbonhome.com/2018/07/what-is-the-carbon-footprint-of-natural-gas-heating-oil-propane-and-coal/

Written Answers to over 300 Questions about Zero Carbon Homes:https://greenzerocarbonhome.com/webinar-questions-and-answers/

Finance and Net Zero Energy Terms explained: https://greenzerocarbonhome.com/energy-and-finance-terms-explained/

Zero Carbon Home Website Home Page:                https://greenzerocarbonhome.com

Database of State Incentive for Renewable Energy (DSIRE) https://www.dsireusa.org

Published articles on Zero Carbon and Net Zero Energy:

Department of Energy, EnergySage, “Zero Carbon Home”https://www.energysage.com/project/7230/zero-carbon-home/

Zero Energy Project, “My Zero Energy Retrofit beats my 401k”https://zeroenergyproject.org/2018/09/23/my-zero-energy-retrofit-beats-my-401k/

Cool Effect, “Mr. Green’s Zero Carbon Home”         https://www.cooleffect.org/content/news/green-testimonial?utm_source=Cool_Effect_CRM&utm_medium=EMAIL&utm_campaign=20180814Engage_Testimonial&utm_content=green_CTA

Green Energy Times, “My Zero Energy Pool is a Great Investment!” http://www.greenenergytimes.org/wp-content/uploads/2019/05/GET_May-2019.pdf

Published Presentations on Zero Carbon Zero Bills:

To see a 3-minute interview of David Green by NBC Boston anchor Joy Lim Nakrin, please click here:TV interview

To see a 20-minute TED talk at Harvard Business School, please click here: TED Talk

You can watch a recorded version of my Zero Carbon, Zero Bills webinar here: Zero Carbon, Zero Bills Webinar

Reviews of my “Zero Carbon, Zero Bills” webinar included, “Minute-for-minute, point-for-point, one of the best webinars I have ever attended. Thank you!”, “David is a true inspiration and asset to our community. He inspired us to get solar panels and a new front door”, “This is like a masterclass in ZeroCarbon”, “Thank you soooo much for the sensible advice and your fabulous resources!!” and, although this next comment is a little flowery, it does express the sentiment of many other comments, “Your contribution to Greening America is great and will probably help our survival as a species a bit longer than expected”.

The below description of actions taken by a MA-based homeowner shows just how much you can do by being attentive to energy use in a home, before adding things like heat pumps and solar panels.

I have reviewed cursorily your well researched and detailed Green plan. I would only offer, from my less informed point of view, a slightly different perspective for you to consider. If it appeals, perhaps you could devise tables and guides to make it useful for those in similar situations to mine. 

Your thrust, as I interpret it, is to “invest” in actions that reduce the use of fossil fuels by the most efficient means available, taking into account cost and payback.

My approach is two-pronged, namely 1) Conservation and 2)Investment in Efficiency. 

For example, my house, built in 1957, 3169 sq. ft. living area, 2×4 walls, 2x 8 floor joists, and 2x 10 rafters has been insulated and weatherstripped thru a MassSave contractor, (walls were too narrow to add insulation). Windows are double pane, insulated. Blower door tests showed a reduction from 5k CFM to 3.5k. 

Oil-fired hot water baseboard, which I put in in 2000, 12k LG mini-split, 3-ton Trane central air for the upstairs, connected to existing ductwork. Electrical panel is 100 amp.

Electricity usage, 3600kw/year. (Note that I pay about $0.43/kw, due to fixed delivery charges and add ons). Oil, about 400 gal/yr. Propane c.40gals/yr

To reduce carbon footprint, thus save money, we two occupants keep doors closed, in rooms we either don’t use, or wish to heat comfortably while occupied, supplementing with electric space heaters. We keep the heat “off” in the second floor heating zone, save for briefly bring temp up to 64 at bedtime. Hot water source is via propane stove heated kettle, save for necessary ablutions, or guest visits when we keep the 40-gallon hot water heater on. (Runs off the oil furnace)

Each year I look for ways to lower our electrical and fuel needs without impacting lifestyle. For example, I have always felt it unnecessary to run the 40-gallon hot water heater, off the furnace. I did winter/summer Hi-Lo setbacks on the furnace temp, and used the furnace on/off outside of heating season. Then, Last year I installed a twenty gallon electric hot water heater which serves nicely in place of the forty gallon one for about three seasons. It’s also installed closer to the bath/shower, thus avoiding a need to draw off any cold water. (We must do that with the large HW heater, but save the water in a bucket for plants.). This winter, I added another fuel saving step. I attached an on-off switch to the furnace powered hot water heater, thus powering it up the few times it’s needed each week. I figure this saves not only fuel, but the corresponding electricity necessary to run the burner. 

With virtually no exceptions, we air dry the two loads of laundry each week, either clothesline or air dryers in basement and in front of wood burning fireplace insert .

I do expect to have to replace the 3-ton central air unit at some point, even though the replacement compressor is only ten years old. The coolant, I learned, was ordered “discontinued” by the US government, in 2010. How Trane was allowed to sell me a new unit in 2013, I will never know. Last year I had the unit serviced, and was charged $400 for one pound of coolant. Thus, I have decided to keep it going until it dies, unserviced, which could last another ten years, given that it only lost one pound in the first ten, and the services did not detect the source of a leak. Be that as it may, I’m prepared to spring for a mini split replacement, which will be far more efficient and cheaper to run than the central unit. (It will also save on fuel oil in the heating season).

Oh, and as an FYI, for emergencies I have two portable generators, 3500 and 4700 watts which hook into relays powering everything in the house.  

Six sixty-gallon water barrels supply water for plantings, garden and lawn outside, car washing, etc. 

One final point. Today’s footprint analysis could take into account auto use, as EVs are part of the equation, and one must consider “fueling” at home. At some point I expect battery storage will be advanced enough, so a small solar collector could supplement the mains for charging and supplementary utility, like lights, TVs, etc. in an emergency situation, or for charging an EV.

Our All Electric Home

I know from our experience that one can a) use heat pumps with no fossil fuel backup in our New England climate and b) taking certain measures (those “variables”!), can make all electric heating (and cooling!) “affordable”.

We live in a good situation for home energy comparisons — a condo development with 26 almost identical two story duplexes built in the mid 1980s with all electric heating (no gas or oil).

Each home had two big heat pump compressors at the side of the building with one heat exchange unit in the basement serving the first floor and one in the attic serving the second floor, both providing forced hot (or cold) air through ducts. There were also a few (we had three) baseboard resistive heat units installed in areas hard for ducts to reach. The old heat pumps could also use resistive (expensive) heating if they could not keep up.

Around 2014, our Eversource bills told us we were consuming far less electricity than our average nearby neighbors.

No doubt this was because we already did these:

1- Had energy efficient lights and appliances
2- Turned off items when not needed, including light polluting outdoor lighting
3- Dried our clothes on drying racks rather than in the dryer
4- Kept the thermostats low and wore warm clothes in the winter
5- Opened windows in the evenings and closed them in the mornings during cool summer nights, rather than than using the AC
6- Avoided wasting hot water when showering or washing dishes
7- Disconnected the wiring to our inefficient resistive baseboard heating units

All the buildings have had Mass Save coordinated improved air sealing and attic insulation installed, an important measure.

In 2015 we sought to do even better, by installing a single ductless mini split and stop using our ducted system at all.

We installed a single 15K BTU ductless mini split in our living room, an open area near the kitchen. (cost after rebate about $3,600) The installer argued this would be insufficient for the whole house but we wanted to try it anyway.

After 2015, we used only this one mini split for heating and cooling for the whole house. We kept the living room at about 68 degrees in the winter. Enough heat drifted up the stairs to the second floor to keep it cool but usable for two bathrooms, office and bedroom at around 62 degrees in the winter. We had absolutely no heat in the basement which is cool (but not close to freezing) in the winter, being largely below ground. We were and are satisfied.

With that change to the mini split, our electric bill was 28% lower for 2016 than it was for 2014.

If we had chosen to put a mini-split in each major room, the installation cost, after rebates, would have been much higher and the operating cost would also have been higher.

We know we are paying 1/2 or less of what some of our condo neighbors are paying, as some have shared their electric bills with us. Our biggest electric bill of the past year was for January 2023 for $308. One neighbor paid over $1,100 for that month! None have chosen to replace their ducted systems with mini splits.

Other factors to consider:
• We are just two retired persons
• Philosophically, we are fine with a bit less than 100% comfort.
• We do not inhabit the basement
* Larger families would probably need more mini splits and use more energy • Our 1st and 2nd floor lived in area is 1,200 sq feet.

In Conclusion

Our “minimalist” approach may not be for everyone, but it was very affordable and we feel good about having less of a carbon footprint than probably any of our nearby neighbors. If one used this minimalist approach switching over from gas heat to a mini split, the outcome should be the same

Note: Our percentages and numbers have been adjusted to remove the impact of the two EVs we charge at home. Also, once in a while as a treat for the coldest winter evenings, we run our wood stove for a few hours, but that has been a constant over many years and would not affect the reduction numbers we saw in 2016.

Hi Alan, sorry to be so late getting back to you on your experience with heat pumps. I believe we are both right at the same time. Under some circumstances (fairly modern, well insulated construction with internal party walls like in your condo) you can get by on heat pumps alone if you can tolerate some cold days in winter. If our house was at 65F I would be divorced. I might be able to squeak by on heat pumps alone if I could tolerate 65F. But I can’t keep our detached home at 70F on the heat pumps alone if it is below about 20F out. I manage this very carefully (eg I put the furnace on for an hour) and have got our annual heating oil use down to about 30 gallons a year. Before the “Fab Four” it was 3,000. So even a detached house at 70F is very close to being able to be heated year round in MA with heat pumps alone. Even if it can be done, it gets very expensive because heat pumps get less efficient at low temperatures. The economic cross over point (the temperature below which it is cheaper to heat with natural gas) is often around 30F. So, even if it can be done, it is very expensive to do so. 

The question on generators is timely. I have a very old generator that I can no longer get parts for. It no longer works. I ordered a Tesla Powerwall battery to be integrated with my solar panels to replace it. I cancelled that when I realized that the Ford F150 Lightening is designed to be a back up generator for a house. After 2 years on order, the Lightening was delivered in October. One way to use the Ford as a back-up generator (which Ford recommends) is to have their solar/battery partner, SunRun, install the battery/inverter/charger hardware for you. Unfortunately this costs $10k. However, the F150 comes with a 30A/220V electrical socket in the bed of the truck powered from its 130kWh battery. This battery is the equivalent of 9 Tesla Powerwalls. This is designed to act as a back up generator. Because of my existing (defunct) generator I already have the wiring for the emergency panel and the transfer switch. If you have had a generator in the past then you have this wiring too. I had my electrician install a connector on the side of my house which connects the truck to the emergency panel. It was a little tricky to get it running, but I now have 3 days worth of power during a grid outage. This is not running the heat pumps, I still have my oil furnace for these occasions. If I were to run the heat pumps on the Ford I would probably trip its breaker and, even if it did not trip, the battery would last maybe one day. 3 days of power is great if you are home, but we also go away for up to two weeks. The Ford’s battery will not last 2 weeks. Hence I am going to get my electrician to install an automatic transfer switch so that the Ford’s battery is only used when the grid is down.

An alternative is to install the battery/inverter/charger with your solar panels. Ask GS for a quote on this. If the battery can be recharged from the solar panels during a grid outage then even a much smaller battery (like a Tesla Powerwall) could power your house for a very long time, though probably providing enough heat from the heat pump to keep the house from freezing rather than keeping you toasty warm. Ask them what their experience is on this. Especially what happens at night (will the panels produce enough electricity during a cloudy day in winter to charge the battery enough to provide heat at night), and what happens if the panels are covered in snow.

I have explored many different option for batteries and generators. There is no perfect solution and all solutions are expensive. You can cover some scenarios for providing power during a grid outage, but there is no solution that covers all scenarios, particularly ones where you are away for long periods and we also have a grid outage that last more than a day or so.  Remember that gas-powered back up generators regularly fail to start in cold weather (even if they have been regularly serviced, I speak from experience) and run out of gas. 

I think the F150 with an automated transfer switch is the best option (for us) because it is relatively cheap (maybe $1,000 on top of the Ford) and can last 3 days even with thick snow. But this only works if your EV supports home charging. Today only the F150 really does (Nissan claims the Leaf can but I am skeptical), but most manufacturers (including Tesla) have announced that they will support vehicle-to-home (V2H in the lingo) in the future. If you see an EV in your future, which you mentioned you did, this is likely the best option. However, it could be a few years away and that means you need a back up plan for heat in arctic cold weather during a grid outage before you get the EV with V2H. The realistic options are a gas-powered generator (with enough output to run the heat pump) or a propane heater. 

Green Lawn Mowing

We have switched our lawn-mowing service from a company that uses traditional gasoline-powered mowers to EcoQuiet Lawncare that uses only electric, battery powered mowers. We will never go back to gasoline. 

The new mowers are far quieter than the old ones and produce no exhaust fumes. The cost-per-mow is about 20% higher than it was with the the gas-powered mowing company, but we are doing fewer mows per season so the per-season cost is about the same.

In this video (below) you can hear how low the noise level from the battery-powered mowers. Note that Kyle is not wearing ear defenders. It was quiet enough that I could hear Kyle singing to himself. 

For Kyle and Brandon, the biggest benefit is not the low noise but not having to breathe toxic exhaust fumes all day. Their lungs will stay healthy and they will retain their hearing far longer than the workers for our previous gasoline-powered lawn mowing company. 

They are eagerly awaiting the arrival of their Tesla Cybertruck because it can charge the mowers from its 220V outlet. The Ford F150 Lightning (which I got a month ago) can do the same. The Lightning can run my house for 5 days on its enormous 130kWh battery. It has a 220V / 30 Amp AC outlet in the bed of the truck that my electrician is going to wire into my emergency panel. It can sit 5 adults comfortably (there is no tunnel under the middle seat in the rear) and I can get four kayaks in the bed of the truck.  The Lightning can be had (with a smaller battery) for $57,000 retail less $7,500 federal tax incentive (which you can take at the point of sale from Jan 2024) and a $7,500 MA rebate making the net cost $42,000. A new F150 gas-powered truck is $46,000. Did I mention I power the truck from my solar panels? Hence both my house and cars have zero carbon footprints. We also have a Tesla Model S.

Our new lawn-mowing service is EcoQuiet Lawncare. If you are interested you can contact the owner George Carrette at 978 201 0061.

And here is Kyle mowing the grass. He is not wearing ear defenders and I could hear him singing to himself! They are that quiet!

Here are Kyle and Brandon with their new Greenworks battery-powered lawn mower. It is towing an aerator/overseeder so we can help our grass win the battle with the dandelions.

Please note that I have no financial relationship with EcoQuiet, I simply am recommending them based on our experience.

My new Ford F150 Lightening arrived today (after 2years!). It is an awesome vehicle! The net price after Ford’s incentives, the federal tax credit and MA rebate is $61,000. That is the same price as a new BMW X5. It is replacing a 12-year old BMW X5. The X5 is costing me thousands of dollars a year in maintenance. The F150 Lightening will cost me almost nothing because it has no engine, gearbox, clutch, radiator, alternator or spark plugs to fail. Because I charge it from my solar panels I can drive it for about 2c per mile whereas the X5 costs 20c per mile. It connects to the Tesla supercharging network (and EVgo and Chargepoint) for long-distance travel. It has a 130 kWh battery that will power my house for 5 days during a grid outage. It is made in the US with UAW labor. Did I mention the zero-carbon footprint? I can run 4 x 120V appliances from the bed of the truck. A fridge (margaritas, beers or a chilled glass of bubbly anyone?), a microwave (hot dogs) a coffee pot and a TV projector make for awesome tailgating! This truck is a party on four wheels! It could also run a circular saw, a mitre saw, lights and a shop vac. It is a workshop on four wheels! Oh, and I can get four kayaks in the back. 

I will be doing a talk for Sherborn on EVs and Vehicle-to-home electrification in January. This is the wave of the future. No more maintenance, no more emissions, no more back up generators! And lots of parties.