It’s a simple idea, but it’s not quite that simple.
When it gets to be around freezing outside, you have to deal with frost buildup on the outdoor unit.
And as temperatures fall, output and efficiency generally falls. So you need an oversized unit to heat your house on the coldest days, but an oversized unit isn’t great the rest of the year.
Historically, heat pumps were only good if it never got down below freezing. Now, modern cold- climate heat pumps are efficient well below freezing and Mitsubishi’s models advertise that they deliver 100% of their output down to -23F/-30C. Between adding variable inverters, better defrosting, etc they’ve come a really long way in the past decade.
Typical naive Australian. What you would consider unbearably frigid is warm by northern standards. It wasn’t until recently that heat pumps were efficient enough to compete with wood and coal furnaces.
Reverse-cycle ACs have had >100% heating efficiency since the 1990s. America just seems to take forever to embrace anything environmentally friendly (reverse-cycle AC, solar hot water, rooftop solar, etc…).
> 100% efficiency doesn’t mean much when you consider that the generation and distribution of electricity is not efficient. It wasn’t until recently that heap pumps became efficient enough to beat onsite burning of fuel.
It wasn’t until somewhere in the last 15 years that air type type heat pumps, as opposed to ground loop, could cope with the cold temperatures in the northern states without having to fall back to resistive heating for weeks at a time.
When you have to run resistive heaters the electrical usage skyrockets and makes a heat pump system vastly more expensive to operate.
If you live in a cold State, Zone 6 or higher, then you need to be careful when purchasing an ASHP to make sure that it has an HSPF of 10 or greater. If it doesn’t then you’ll be paying big electrical bills trying to keep your home warm. Those units are also more expensive to purchase than a regular Heat Pump like you would run down under.
Frankly nowhere in Australia experiences cold anything like what I do on a yearly basis. The coldest temperature ever recorded anywhere in your country was a mere -9f. Here in the United States there’s quite a few places where that is a common daytime high temperature in the winter, even in the lower 48. There’s quite a few places even in Zone 5, see previous map, that will get to -9 and stay there for days at a time.
It’s not uncommon for overnight lows in Zone 6+ to hit -20f and temperatures even lower are definitely possible. At my house in Wyoming last winter we touched -40f / -40c for a some hours one night.
Air type heat pumps simply could not handle those kinds of temperatures until relatively recently. That’s why so much of the US doesn’t have them already. They just didn’t work during the winter in northern half of the country.
When you have to run resistive heaters the electrical usage skyrockets and makes a heat pump system vastly more expensive to operate.
More expensive than a heat pump without a backup/additional electrical resistance heater. Not more expensive than an electrical resistance heater on its own.
That’s what’s so strange about this, in most cases a heat pump would be replacing a non-reversible AC and an electrical resistance heater or gas-fueled furnace. And in nearly every case, even with the need for a backup/additional resistance heater, you’re still saving money. And it’s not like any of this is new technology, it just took forever for it to become popular in the US.
They are completely standard in large parts of the US too–just the northeast and other colder areas haven’t started using them due to their colder winters.
This is about one state in the far north pushing to get them into more houses. Older heat pumps would not have been very effective there for most of the winter. Newer models can still produce heat in much colder temperatures, so they are adopting them.
It gets below zero in the north east in the winter. Heat pumps stop working at 20-30F and the system has to switch to classic/emergency heat. They are great for fall/spring (or summer as an AC), but useless for winter.
The bigger issue is that it is extremely expensive to install ductwork, wiring for 1 or more thermostats, and a shiny new heating/cooling system in many existing homes that use classic radiator heat. Depending on where the oil tank is located, it may require removal as well (example: if it is underground, depending on state/municipal laws).
That’s not necessarily true now the newer systems can go to as low as -15F which in the north only happens for a few hours a year so still a reduction in heating gas/oils needed
Heat pumps = simply running your AC in reverse
It escapes me such a simple concept could take so long to be considered for homes instead of radiators
It’s a simple idea, but it’s not quite that simple.
When it gets to be around freezing outside, you have to deal with frost buildup on the outdoor unit.
And as temperatures fall, output and efficiency generally falls. So you need an oversized unit to heat your house on the coldest days, but an oversized unit isn’t great the rest of the year.
Historically, heat pumps were only good if it never got down below freezing. Now, modern cold- climate heat pumps are efficient well below freezing and Mitsubishi’s models advertise that they deliver 100% of their output down to -23F/-30C. Between adding variable inverters, better defrosting, etc they’ve come a really long way in the past decade.
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We have them in Florida. It’s just very cold in the Northern USA.
Typical naive Australian. What you would consider unbearably frigid is warm by northern standards. It wasn’t until recently that heat pumps were efficient enough to compete with wood and coal furnaces.
Reverse-cycle ACs have had >100% heating efficiency since the 1990s. America just seems to take forever to embrace anything environmentally friendly (reverse-cycle AC, solar hot water, rooftop solar, etc…).
> 100% efficiency doesn’t mean much when you consider that the generation and distribution of electricity is not efficient. It wasn’t until recently that heap pumps became efficient enough to beat onsite burning of fuel.
It wasn’t until somewhere in the last 15 years that air type type heat pumps, as opposed to ground loop, could cope with the cold temperatures in the northern states without having to fall back to resistive heating for weeks at a time.
When you have to run resistive heaters the electrical usage skyrockets and makes a heat pump system vastly more expensive to operate.
If you live in a cold State, Zone 6 or higher, then you need to be careful when purchasing an ASHP to make sure that it has an HSPF of 10 or greater. If it doesn’t then you’ll be paying big electrical bills trying to keep your home warm. Those units are also more expensive to purchase than a regular Heat Pump like you would run down under.
Frankly nowhere in Australia experiences cold anything like what I do on a yearly basis. The coldest temperature ever recorded anywhere in your country was a mere -9f. Here in the United States there’s quite a few places where that is a common daytime high temperature in the winter, even in the lower 48. There’s quite a few places even in Zone 5, see previous map, that will get to -9 and stay there for days at a time.
It’s not uncommon for overnight lows in Zone 6+ to hit -20f and temperatures even lower are definitely possible. At my house in Wyoming last winter we touched -40f / -40c for a some hours one night.
Air type heat pumps simply could not handle those kinds of temperatures until relatively recently. That’s why so much of the US doesn’t have them already. They just didn’t work during the winter in northern half of the country.
More expensive than a heat pump without a backup/additional electrical resistance heater. Not more expensive than an electrical resistance heater on its own.
That’s what’s so strange about this, in most cases a heat pump would be replacing a non-reversible AC and an electrical resistance heater or gas-fueled furnace. And in nearly every case, even with the need for a backup/additional resistance heater, you’re still saving money. And it’s not like any of this is new technology, it just took forever for it to become popular in the US.
They are completely standard in large parts of the US too–just the northeast and other colder areas haven’t started using them due to their colder winters.
Lots of houses in the US have heat pumps already.
This is about one state in the far north pushing to get them into more houses. Older heat pumps would not have been very effective there for most of the winter. Newer models can still produce heat in much colder temperatures, so they are adopting them.
It gets below zero in the north east in the winter. Heat pumps stop working at 20-30F and the system has to switch to classic/emergency heat. They are great for fall/spring (or summer as an AC), but useless for winter.
The bigger issue is that it is extremely expensive to install ductwork, wiring for 1 or more thermostats, and a shiny new heating/cooling system in many existing homes that use classic radiator heat. Depending on where the oil tank is located, it may require removal as well (example: if it is underground, depending on state/municipal laws).
Yeah crappy ones. This does not apply to the ones designed for cold climates. Mine still beats electric radiators in efficiency at -22f
That’s not necessarily true now the newer systems can go to as low as -15F which in the north only happens for a few hours a year so still a reduction in heating gas/oils needed
I know the guy in the TC video used Chicago as an example but the “few hours a year” thing simply isn’t true for many of us.
Where I live we had many days below -15f including a week where itpretty much stayed between -20 and -30 for nearly a week straight.
A Heat Pump will still work, even here, but you need to be careful about which one you purchase and how it handles cold weather.