[swimorsinka]

Ugh, I think this is a terrible idea for heating.

I've installed 2 Mitsubishi hyper heat pumps in the past 5 years with 3 indoor heads totaling ~48,000 BTUs of heat capacity. I don't think people understand how much more expensive heat pumps are than a traditional natural gas furnace. I paid $25,000, and that was 5 years ago. This is for a small house of 1500 square feet. If you had a larger 3 or 4,000 square foot house, you can double or triple that price. In contrast, I know you can get a 250,000 BTU gas boiler for ~$20,000 with install.

Plus, electricity is still way more expensive than gas, even with the price shocks over the past year and even with the high efficiency of modern heat pumps. And it's not that green, given that you lose ~7% in transmission, and usually it's coming from a coal or natural gas plant. If you had solar to offset some of it, that would be great, but usually there isn't enough sun in the winter to account for all of your heating needs, at least without a gigantic array.

I think this is pretty impractical and misguided. I've tried to be green, but next time I buy a house, I'm going to try to go back to a gas furnace.

[yathern]

Sounds like you gave it an honest try and it wasn't good for your setup - won't argue that. I do think it's something that depends very greatly on your climate, local costs/subsidies, and your house.

I also want to shed some light on why heatpumps can be great - by disagreeing with this statement:

> you lose ~50% in transmission, and usually it's coming from a coal or natural gas plant

Heat pump performance is often rated in terms of COP - a number that indicates how much more heat it generates than the energy it consumes. A COP of 4.0 means that for every Watt of energy, it produces 4 times that much heat. This is thermodynamically possible because a heat pump removes energy (makes cool) the other end. It depends largely on the temperature outside, and the individual device. Follow along with me for some cool results of this:

- Natural gas to electricity is about 85% efficient.

- Transmission losses are close to 10%

- So your house gets (roughly) 75% power efficiency.

- Natural gas furnaces are basically 100% efficient (almost all heat from burning goes into your house)

- A medium-good heat pump can expect to get a COP of 3.5 on a 30F day

With all these assumptions, let's do a little test:

- Let's burn a gallon of natural gas in your basement, using 100% of the energy it has.

   -  We get... about 64 BTUs

- Now let's have a power plant burn that gallon and send the electricity to your house at 75% efficiency.

   -  We get 14 Watt hours...

- Now let's put those 14Wh into a heatpump with a COP of 3.5...

   - We get 167 BTUs!!

That's right - the same gallon of gas burned in a power plant will produce more heat in your house than if you burned it right there. Which sounds basically like magic, but it's of course because a heat pump doesn't create heat, it moves it.

Now, whether it makes sense for a given customer has a lot to do with the price of gas, the price of electricity, the price of furnaces vs heat pumps, and the temperature outside (COP can drop down significantly if you live in an extremely cold place). However, if you need an AC, it makes sense to at least get one that can dual function as a heat pump, this way it can be your source of heat in the spring/fall, without having to use the more powerful burner.

[rjdagost]

Then there's the question of how the electric grid will sustain this significant new increase in demand. As with mandates banning gas cars, the grid supply and stability is always regarded as a mere detail to be sorted out later.

[Thorrez]

>And it's not even green, given that you lose ~50% in transmission

Source? I thought the loss was much lower than that.

[swimorsinka]

Looks like you’re right. This https://insideenergy.org/2015/11/06/lost-in-transmission-how... claims it’s only 7%. I’ve updated the original comment. You still have the problem of non green generation sources, and you could still do better with a high efficiency gas furnace on-site, although I think most people go with low efficiency (~80 or 85%) units.

[Thorrez]

Even if electricity is generated with gas, and with the energy lost in the generation and transmission, with a really good heat pump and optimal conditions, it could outperform a gas furnace, because a heat pump can be more than 100% efficient.

https://en.wikipedia.org/wiki/Coefficient_of_performance

>The efficiency of air source heat pumps is measured by the coefficient of performance (COP). A COP of 4 means the heat pump produces 4 units of heat energy for every 1 unit of electricity it consumes. Within temperature ranges of −3 °C (27 °F) to 10 °C (50 °F), the COP for many machines is fairly stable.

>In mild weather with an outside temperature of 10 °C (50 °F), the COP of efficient air source heat pumps ranges from 4 to 6.

https://en.wikipedia.org/wiki/Air_source_heat_pump

[Spooky23]

It’s complicated.

If you’re talking about transmission between a nearby generation facility and end user, losses are low. If you’re talking about losses in April/May, it’s low. The statistics are difficult because the average losses don’t matter, it’s the marginal losses that matter. In mid-August when electricity demand peaks, you need to generate twice as much electrify at a higher price to get another marginal unit of electricity.

For New York, which is planning to ship power in from Quebec, losses at that distance are very high, and require significant investments in new transmission infrastructure to improve yield. At one point, shipping additional grid supply from far away to NYC resulted in losses as high as 65% in certain weather conditions. That’s why so much was invested in peak load reduction… stuff like voluntary shutdowns in exchange for discounts, efficiency programs, etc. Every dollar invested there avoided like $7 in infrastructure investment.

[pg_bot]

Hmm you should've only needed a 3 ton unit for that amount of square footage and those cost about 2-5k. Was there some other kind of work that needed to be done that you aren't mentioning? You should've seen prices around 8k for the unit plus installation.

[swimorsinka]

You might be thinking for the non hyper heat modules. The ones I’ve got still heat down to -13 F. I remember thinking the same when I was originally pricing out the units. But when you actually get them through a reputable installer with a warranty, that roughly doubled the price. I quoted 3 installers at the time and they all came in at roughly the same price.

I started with a 30,000 BTU unit in 2 of the bedrooms and then added another 18,000 BTU unit later. My house is a split level which makes it a huge pain to heat. The price of the first units was ~$15,000 and the second one was ~$10,000. Nothing special as part of the installs.

[pg_bot]

Hyper heat are typically 5-10% more expensive than regular heat pumps.

[ploxiln]

Natural gas distribution is also leaky, IIRC, and the amount of gas released into the atmosphere is significant. So I wouldn't say electric heating is not "greener", I'm pretty sure it is.

But electric is way more expensive. Natural gas is so cheap (n the northeast US). If it was practical, I'd also seriously switch back to gas powered hot water heater and furnace. A couple years ago I moved from an Apt with hot water and heat included for free from a gas-powered boiler in the basement, to a Condo with its own electric hot water heater and heat-pumps, and it was a bit shocking how much more expensive it is to heat with electricity ... like (very roughly) $30/mo vs $200/mo in winter

[nonethewiser]

It’s absolutely a terrible idea for heating. Natural gas is obviously the better choice - that’s why it’s used and they had to make it illegal to prevent it.