Electrification in US climate zones 1-4 is pretty straightforward. Often insulation upgrades aren’t strictly required.

In climate zones 5-8 it’s much trickier. Shell upgrades are often required to keep operating costs down.

~50% of resi gas use is in 5-8.
At present insulation upgrades don’t result in predictable resale value increases.

Until this changes, don’t expect scale in retrofits. 150-200k/year maximum.

The solution is simple: publish energy use at resale.

My 2016 article still holds: bit.ly/EUIonGTM
In the short term, hybrids can help any home reduce gas use 30-90%.

Hybrids (heat pump plus furnace) also get contractors and consumers used to heat pumps so full electrification is less scary.

Fairly cheap policy can drive this: bit.ly/3Hprogram
The near term challenge though is getting HVAC contractors and their homeowner clients on board.

This requires a heady and carefully executed mixture of education, diagnostics, and sales process which is what HVAC 2.0 provides. See this for more: bit.ly/HVAC20overview
So the key takeaways are that we can’t electrify without tackling cold climates, resale value is critical to scaling performance retrofits, hybrids are the shortcut, and HVAC 2.0 can do the selling of both HVAC and shell upgrades.
Last key point: we have to start addressing the mass market today, the time for targeting early adopters only is past.

This is another thing we’ve designed HVAC 2.0 to do.

Much more in the course in my handle, be sure to watch the process video above too.

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More from @energysmartohio

20 Dec
First experiences with induction are really important.

Here's a recent review of our Ohio house, note their experience.
What if there were thousands of homes like this? How fast could #electrifyeverything spread? @Airbnb could help a lot with a new class: bit.ly/AirBnbElectrify
While part of me hates that we are taking 2 housing units off the market in WV right now, we're giving them much needed love after 20-30 years of neglect that doesn't pencil if they were long term rentals, so we're improving and electrifying old housing stock. Important note.
Read 7 tweets
30 Nov
This is what code enforcement looks like.

2015/2018/2021 IECC (insulation codes) are all good enough.

But they’re not enforced, and it’s gonna be TOUGH.

But some are looking for opportunities like this fellow. Image
It’s really tough to fudge leakage tests, so it’s a key tool.

Although duct leakage in northern homes with ducts in heated space doesn’t matter all that much. While home air leakage does.

Down south with ducts in attics, both duct and home leakage matter.
Most southern new home duct systems are abortions btw. Kinked flex duct with almost no flow that get drywalled into the ceiling and can’t be replaced without nearly gutting the house. Passes the test though…

Energy use will tell the tale of bad installs though…
Read 4 tweets
19 Feb
THREAD:

Homes as thermal batteries aka resilience.

This house dropped 20 degrees in 8 hours in similar 30-40F temps during the Hurricane Sandy outage in 2012. It took 2 days to recover.

Post project it took 26 hours to drop 10 degrees.

@lloydalter
This is a ~2000 sf 1950s Cape Cod in Cleveland Heights.

Full case study on the insulation and air sealing project we did here. It was about $20K and was focused in the attics of this house (it has 4, or was it 5?)

bit.ly/1959CapeCaseSt…
The house started off really leaky at 5800 cfm50 blower door. We got it down to 3100 cfm50. Still not great, but far better. And good enough it turned out.

The house fundamentally changed. The second floor wasn't 10 degrees warmer in summer anymore, it was within 2-3 degrees.
Read 16 tweets
17 Feb
Tight well insulated homes perform well, exhibit A:

This 5000 sf new home in Cleveland with an 80kbtu 98% furnace and 4 ton heat pump is only at 67% capacity at 8F. That’s about 53kbtu/18kw output.

A 4 ton heat pump would be appropriate here. For a huge house! ImageImage
As we discuss resilience, air tightness is important. This house clocked a 1025 cfm50 blower door or about 1 ACH50.
Exhibit B: 2300 sf 1950 built ranch. 3 ton heat pump. 2000 cfm50. This heat pump shuts down automatically below 3 F. 5 kw/15,000 btus of backup heat is handling the house at this moment. ImageImageImageImage
Read 5 tweets
17 Feb
THREAD:

As painful as it is to watch what's going on in Texas, the residential solution basically looks like what we should be doing anyway:

-Tighter, more efficient homes
-Smaller, more efficient HVAC
-Batteries
-More local generation like community solar

Hard to sell tho!
The fact of the matter is we humans don't change until the pain of not changing is greater than the pain of changing.

In residential resiliency creating a comfortable, healthy, and efficient home is a great deal of work. Work that few contractors are good at selling or doing.
The situation in Texas brings up very valid concerns about electrification - how do we handle the really tough cold snaps?
Read 27 tweets
21 Jan
A Heat Pump Policy Thread:

What if we paid resi HVAC manufacturers ~$400 per AC they manufacture if they make all of their production heat pumps?

Currently US OEMs make ~5M ACs and ~3M heat pumps. What if they were all heat pumps?

This might only cost ~$10 billion over 4 yrs
We think of residential electrification in "Two Clocks".

The first is getting to where 100% of installs involve a heat pump. Doing that by 2030 is REALLY HARD.

The second is running through all inventory, which will take ~20 years.
Every 6 seconds a new piece of residential HVAC starts up in the US.

That opportunity is lost until 2035-2040.

The faster we can move to 100% heat pump installs, the better.
Read 17 tweets

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