Heat pumps are now mandatory in new homes in Washington State | Hacker News Reader

Heat pumps are now mandatory in new homes in Washington State

electrek.co

32 pointsmfiguiere48 comments

>New homes in Washington State are going to save money up front due to rebates and tax credits and they will also save money in the long run, as heat pumps reduce electricity consumption by up to 50%. Emissions will be cut as well.

This is from the article and it's a little disingenuous. Yes, heat pumps reduce electricity consumption compared to resistive heating which almost nobody in my corner of washington is using. People here use natural gas which is historically pretty cheap even compared to relatively cheap electric rates for heating purposes.

If your goal is to reduce emissions, great. But eventually these tax credits will expire and this will directly translate into people paying more for heating. In the part of the state that influences elections and policy that's not a big deal, but the eastern and central parts of the state get awfully cold from time to time comparatively. Let's not rush to pat ourselves on the back just yet and let's not pretend this policy doesn't have a real human cost.

The article does mention that 56% of Washington residents use electric heading

The data source is based on occupied housing units, not residents: https://data.census.gov/cedsci/table?t=Heating%20and%20Air%2...

This may skew the stats if units without gas tend to be smaller (and need less heating), e.g. if it's predominantly condos that lack gas heating.

According to that same data source 27% of California's occupied housing units are heated with electricity. That is much higher than I would have expected.

How much do y'all pay per kilowatt hour for electricity? IIRC you guys have lots of cheap hydro power.

10c

And heating with a natural gas furnace is still far cheaper. Obviously excluding costs of externalities not included in price of natural gas, but they are also not included in the electricity prices. Not that they are easily knowable in the first place.

I used this calculator [1] to compare based on the current price of utility natural gas and an 11 cent/kWh electric cost. The electric heat pump was significantly cheaper, to the tune of hundreds of dollars per year.

[1] https://www.pickhvac.com/hvac/furnace-vs-heat-pump-cost/

It has been a few years since I did the calculations for my place, but if I put in my natural gas price ($1.05/therm), it is coming out near even. At which point, the initial costs and maintenance costs would be a factor, and back then, a heat pump with a capacity comparable to a gas furnace was much more expensive.

So maybe the parameters have changed, but I also like that my gas furnace can be counted on at any temperature, plus it is not subject to electricity outages. Perhaps I would do both heat pump and gas furnace going toward, the furnace as backup for the heat pump and get the best of both worlds.

Another way of looking at that up-front cost is that it's basically an extra $100 when you install an air conditioning system, or that you get an air conditioning system for free along with your heating system. This is very relevant in Washington where we historically didn't need AC but with hotter summers it's starting to become a requirement for comfort. So there are lots of houses that have never had AC that need a system installed.

> gas furnace … is not subject to electricity outages

But isn’t the air-handling fan and perhaps the ignition unit reliant on electricity?

Yes, but I assume those consume sufficiently less power such that they can be operated via a home generator.

Heat pumps can also be run by generators. Typical coefficients of power are above 4, and generators can be in the 30-50% efficient range, so end to end, it's likely you burn less gas via the generator + heatpump route than via the direct heating route.

What kind of gas furnace works safely without electricity? Is that something you had to go out of your way to get?

Sorry, I meant that can work for a somewhat decent amount of time on a reasonably sized generator, since the most power intensive part (heating) will not come from electricity.

11c is only available in certain markets at off peak hours. Our price in WA has never been that low.

I just looked through the last 3 years, and I was charged $0.0816 per kWh every month, and an additional $12 per month for “basic service”. With the $12/month, the per kWh price was $0.098 at most.

A lot of places in WA state are super cheap, as in 12c/kwh in the Seattle area, mostly renewable.

> Cheap hydro power

Hydropower from the Columbia used to be 1/4 of all electricity in the US. Now it's not even enough for the needs of neighboring states.

The electricity to run a heat pump that moves heat where you want it is cheaper than the gas you need to burn to make an equivalent amount of heat. On the very coldest days the efficiency of a heat pump can drop enough for this not to be the case, but over the course of the year an electric heat pump will save you money over burning gas. There are pretty significant environmental costs to burning gas in our homes, less about the combustion exhaust than the total amount of leaks within the distribution system that allow unburned methane to escape to the atmosphere. There's also growing awareness that many classes of gas appliance produce a lot more indoor air pollution that causes lung disease (especially in children) than was previously expected.

"The electricity to run a heat pump that moves heat where you want it is cheaper than the gas you need to burn to make an equivalent amount of heat."

This must depend on the relative prices of gas and electricity. What's the threshold ratio beyond which gas is cheaper than a heat pump?

It generally takes less gas to generate electricity, ship it, and run the heatpump than to directly heat the house with gas.

But I don't generate or ship electricity.

I buy both my electricity and my gas from PG&E, and pay whatever price they charge for each. So the question of which is cheaper depends not on the fundamentals of physics of it, but on the relative prices PG&E charges for each.

In California, the heat pump will win, partially due to the mild climate, and partially due to natural gas somehow being even more overpriced than electricity.

I pay PG&E:

* ~$0.35/kWh for electricity

* ~$2/therm for gas (equivalent to ~$0.07/kWh according to a quick search).

Even though I pay 5x the price for electricity as I do for gas, a heat pump will be cheaper?

You get a lower rate (higher baseline) if you install a heat pump ($0.28-0.30; 4x to 4.2x), and the coefficient of power for the heat pump should be well over 4 in California.

Current electricity rates:

https://www.pge.com/pge_global/common/pdfs/rate-plans/how-ra...

Current natural gas rates:

https://www.pge.com/tariffs/GRF1122.pdf

You seem to be on the cheaper residential schedule.

> You seem to be on the cheaper residential schedule.

I'm in San Francisco, so PG&E bills me separately for distribution (provided by PG&E) and generation (provided by CleanPowerSF). We are on a rate plan that has slightly cheaper electricity off peak, and save something like $20/year as a result.

The individual line items on the bill are hard to understand (lots of surcharges and credits), but I can tell you from the totals that my most recent bill shows $0.33 per kWh for electricity (average, including both delivery and generation) and $2.56 per therm for gas.

> The electricity to run a heat pump that moves heat where you want it is cheaper than the gas you need to burn to make an equivalent amount of heat

I'd call bullshit on this.

But looking at the figures in Washington you'd need a air sourced heat pump to average 260%, which is said to be possible.

It wouldn't be worth upgrading, but subsidised installation on new homes could/should work.

> pretty significant environmental costs to burning gas

> gas appliance produce a lot more indoor air pollution

Yes

>The electricity to run a heat pump that moves heat where you want it is cheaper than the gas you need to burn to make an equivalent amount of heat. On the very coldest days the efficiency of a heat pump can drop enough for this not to be the case, but over the course of the year an electric heat pump will save you money over burning gas.

I am not arguing any point you're making other than this. This statement is heavily dependent on how cold your winter is and the relative costs of electricity and natural gas. Some years it might pencil out, but some years it won't . I'm not sure without looking at historical data I could say the ratio between the two with certainty, especially given the typically very cheap natural gas over the last decade (although recently of course this calculus changes!)

I'm just arguing for some nuance - the linked article is breathlessly claiming things that I think we should charitably say are bending the truth a bit. If I had to install a heat pump tomorrow I would do it and it wouldn't impact me, even if it cost a few buck throughout the year. I think most people on HN are probably in that same class. There are a large swatch of people, on the other hand, for whom a few dollars is very meaningful and a temporary tax credit is great and all but when they expire if we are asking those people to shoulder the cost of this decision we should do so carefully.

> As of 2020, 56% of Washington residents used electricity for heating, and 37% of residents used natural gas or bottled, tank, or LP gas.

the majority of Washington residents using electric heating is a far cry from "resistive heating which almost nobody in my corner of washington is using."

The majority of Washington residents live on the Western side of the state - much more mild weather. But out in the Spokane area, winters are much harsher.

"56% of Washington residents"

The source data's unit of measure is 'occupied housing units', so this claim by the article is unsupported.

Any statement that discusses the 'majority of washington residents' almost always could just be shortened to the 'the Seattle metro area' because that's where most people in Washington live. It just to happens that the eastern part of the state also has quite a few people, though, and it's more like Idaho climate than it is Seattle climate.

I think people are unaware how heat pumps get preposterously less efficient the colder it gets.

Once the unit ices over, it's not much better than a resistance heater.

Modern heat pumps have minimum operating temperatures below 0F so they're still going to be providing efficient heat during winter conditions nearly anywhere in the world. Whenever excess frost builds up they run backwards for a few minutes to clean the coils off. This is a far cry from the old days of units that didn't operate well below freezing and ran a defrost operation on a simple timer.

> Whenever excess frost builds up they run backwards for a few minutes to clean the coils off

Yes, and in cold enough weather they can cycle that way all day. They function, but it's not terribly efficient.

The colder the weather the less humidity the air can old, so it's not really that much of an issue. Heat pumps definitely do lose efficiency as the air temp drops, which is why it's important to get one that has a size and minimum operating temperature that's appropriate for your use. Washington actually has an energy code that requires heat pumps be properly sized to heat the house without needing to fall back to resistance heat.

I live in Washington and am very familiar with heat pumps. I am sharing person experience - on cold days you will get much lower than the rated efficiency. In Eastern Washington, it's arguable that it would save you much energy over a resistive heater.

Different models of heat pumps vary wildly in how well they can handle very cold temperatures. Personal experience with one or two different heat pumps is practically meaningless.

The new ones fall back on resistive heating as necessary. It simply doesn't get cold enough for that to be true in the cities on a regular basis.

Yakima and Spokane's record lows are both -25F:

https://coolweather.net/statetemperature/washington_temperat...

Heat pumps that operate down to -20F to -25F are available from multiple vendors. At that point, they switch over to resistive heating. So, on record cold days, the COP is near one, but on an average day (low of +36F), it will be over 3 or 4.

Cold weather heat pumps are relatively new; perhaps you have experience with conventional models?

(Record low for the state is -45F. At that point you want backup heat sources, etc, and the heat pump would probably be outside its operating range.)

A real human cost? This is an exaggeration. Also, are those suffering climate impacts counting in your equations??

> Yes, heat pumps reduce electricity consumption compared to resistive heating which almost nobody in my corner of washington is using. People here use natural gas which is historically pretty cheap even compared to relatively cheap electric rates for heating purposes.

Ya, this made me wonder. I get Seattle, but Spokane? You probably need to install gas heating or a wood burn fireplace since I don't think a heat pump would cut it east of the cascades. But I see how it would do wonders for air conditioning in the summer.

This is especially frustrating given natural gas is still being burned off at well heads. It's still a waste product in the US and priced as so.

I get that heat pumps are excellent, and that there are economies of scale at play for the state run nat gas power plants. But natural gas is still an order of magnitude cheaper in WA State, and having a gas furnace is only marginally more carbon intensive than letting the state burn the gas for you.

I would rather they focus on making power cheaper and more plentiful than this annoying anti-consumer focus.

The orgs who burn gas at well heads should invest in a gas fired power stations then. Too much gas? Use it to make electricity.

I first experienced a window-mounted heat pump a couple of days ago when the new neighbors' house started humming. It was about 40 degrees out when I went outside to where the hum was coming from. The unit in the window was blowing at lot of air at me that was colder than ambient. Not in Kansas anymore!

Heat pumps only work at specific temperature and humidity ranges. Outside of those parameters they don’t work and the air handler usually has resistive heating coils to produce heat. I find radiant heating of ceramic plates like they have in France much better but AFAIK not available in the US.

Current cold weather heat pumps switch to resistive heat at -18F to -25F (-27C to -31C). In high humidity cold weather, they automatically run de-icing cycles.

Radiant heaters are available in the US (gas and electric), but are uncommon (most buildings have central air instead).

Not from my experience.

I have a one year old Carrier 24 SEER Infinity unit. It’s 39 F/69% humidity and resistive heating is on.

That model is not optmized for low temperatures. (And using resitive heatin doesn't imply the heat pump is off, or that the COP is currently 1).

Carrier doesn't say much about cold weather operation, other than that it shuts down at -15F:

https://www.dcne.com/product/infinity-variable-speed-hp-24-s...

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