343. Deep Energy Retrofit - Transforming 1951 home to net-zero

Take a 1951 home, laser scan the exterior, then build new walls in a factory to tight specifications and then plop them right over top of the old walls. The result: a solar-powered, net-zero home with R40 insulated walls that makes money on its utilities. This is the Sandercock family home and a pilot where Butterwick Projects is using the Dutch EnergieSprong strategy of reskinning old homes to easily get them to net-zero.

[mrfusioneng]

We have a 90’s florida home we converted to net zero, but we didn’t spend nearly as much, and anyone can do the work themselves. The home is concrete block construction, ( around 10” thick), we painted the outside a lighter color, and get very little heat loss thru the walls.
The house is 1850 sq ft single story with asphalt roof. We gutted the attic, and all ac ductwork in the attic, ( all the ductwork was suspended in the attic, with r4 insulation, ( built to building codes). We found every duct joint leaked, ( again all to current building codes). The inside attic temp was around 145 degrees during the day. When we gutted the attic we sealed the house, we then re- installed all ductwork using R30 insulation, and all buried under around 25” of blown glass insulation, with all cold air registers and returns encased in 3” of urethane foam. We installed a radiant barrier system 2 layers thick, with accelerated hot air channels to vacate the hot air from the soffit to the ridge vent system. We also put as light a colored roofing on the roof we could find, ( roof used to be black). The attic temp went from 145 degrees down to around 100 deg, ( 5 deg over ambient max). All ductwork was sealed and verified to under 1% loss. We also put temp sensors at the beginning and end of each duct to insure no more than a 1 degree drop from begging to end of each duct.
We installed a water cooled air circulation system that consists of insulated water tanks in the garage, a small water circulation pump, and a heat exchanger in the attic that works by convection mostly, with a small variable speed pwm type variable speed fan to keep air moving thru the attic ductwork, ( with a adjustable 3% fresh air addition, prior to the exchanger. All the hot air in the house rises and comes in thru the ceiling mounted returns. Runs thru the heat exchanger, then cooled air falls out of the ducts throughout the house, after going thru filters and a single pass uv system for air purification, ( allergies in the house). Air is re-circulated around 4-5 times per hour, with a under 3% very slight over pressure. The TES ( thermal energy system), is 100% solar powered from a separate solar system, for both cold water, ( using water chillers), or heating in the winter, ( using peltier based water heater, ( very minor need in south florida)).
The main air to air high efficiency heat pump system was retained in the house, but with it’s runtime hours way less than half the normal run time hours of a regular house.
Many of the other things you did, like heat pump hot water heater, other appliances we also did.
We also heat our pool year round, with a mostly solar based system now, after abandoning the heat pump poole heater.
We have 10k solar on the roof, and our electric bills went from $400 per month down to around $50 dollars a month, ( mostly taxes and fees).
I’m not bragging, I’m just stating that it can be done by anyone, for not a great deal of money, it’s not rocket science.

[dlg]

I have a 1960 brick ranch in Ohio that I'm planning to remodel in the next few years. This definitely appeals to me, but I'm planning a total re-imagining of the entire house, including a whole new floorplan. All that will remain of the old house is the foundation and exterior walls. Even the foundation needs some work, as I need to lower basement floor to increase ceiling height and add code required egress. On order to go net-zero, I will need to remove brick facade (which I was planning to do anyway) and add exterior insulation and probably replace the entire roof with a non-vented design, since I want vaulted ceilings. It seems like it will be too much to to spend on a house that has limited market value, but it will be at least 60-70 percent less than building new. My biggest concern is finding a qualified and affordable contractor for the project.

[ReimagineBuildings]

Fantastic! Great to see the energiesprong concept in action on this side of the pond.

[gambichiang]

He didn’t mention the investment. I am interested to know.

[status-danielho]

Hopefully the few doing the most doesn't dissuade the most from doing a little. I had already done the air sealing and replacing defunct appliances with efficient ones, so I recently upgraded the attic ventilation and insulation of my 80's home. 

I was expecting a 20% reducing in heating and a 13-15 year payback going from R20 to R50. As it turns out, it cut my furnace run time in half (if I know the heat degree days, I know how long the furnace runs that day), and the payback should be 3-5 years. I'll have to wait until the end of summer to see how much my A/C use drops, but it's looking to be around 33-50%.

[KJSvitko]

An energy efficient home or business is more comfortable and saves money in the long run.
Solar energy on your roof combined with battery storage can make people more independent from the grid and natural gas supplies. Add solar and supplemental electric heating or a heat pump for home heating..
Added insulation, triple glaze windows, energy efficient doors, energy efficient heating and cooling systems, energy efficient appliances, LED lighting, smart thermostats, solar panels combined with battery storage and a electric vehicle charger in the garage or car park. People are too focused on the short term costs and miss out on long term savings and comfort. Blower door testing and air sealing are under appreciated tools.Even if you have money to burn you should not waste it. Climate Change will impact everyone. Leave a better future for your children and grandchildren. Join in and speak up for the future of the planet.

[DBRB]

This is needed so bad. There are millions and millions of existing homes that need good ways to become very efficient.

[zigarten]

Awesome! Let's hope the power companies don't start getting cranky about having to buy energy. A long way off I know...

[roberttaylor]

Would it have been less costly to just demo the old stucco and reapply a better air barrier straight to the structure with poly-iso insulation?

[alienwife]

Wait, you keep the old termite, rodent susceptible walls?

[heythere]

What's the oldest net zero building in the US? We're shooting for passive house on our early 1700s hotel, going to net zero would be a nice addition.

[scott]

Without the total cost and payback information, this video is lacking vital information.

[resilientdad]

Great video, I would love a link to learn how I might be able to do this to my house.

[mountainpatriot]

Who can afford this? I would love to deep retrofit my old house. Just removed wood siding and did Hardie board. Need insulation and new windows.

[ByrdNick]

Are there programs like this in the U.S.?

[jasonwilcox]

What did they do to insulate the basement slab? And I assume they also framed interior basement walls and insulated those as well? Great video and concept!

[skylerdylan]

Super cool install. Seems strange to not add a range hood above the stove. Unless its super well hidden. Otherwise very cool. Wondering how the heat pump performs in winter. I've seen air source heat pumps in Edmonton, and they seem to be running flat out. If they're running's flat out all winter, I would be concerned about the longevity, as these systems are not cheap. But perhaps its so well insulated that the heating loads are quite low. So many questions.

[jimmycassell]

Awesome video and technique. Now, how much was it?

[CraigCastanet]

Should have been metal roof, right? to keep the attic cool?

[Gwerd]

Superfantastic! What were the overall costs and payback cycle?