Published Monday in the scientific journal Joule, the research found that heat pumps are two to three times more efficient than their oil and gas counterparts, specifically in temperatures ranging from 10 C to -20 C.
Oxford study proves heat pumps triumph over fossil fuels in the cold::Published Monday in the scientific journal Joule, the research found that heat pumps are two to three times more efficient than their oil and gas counterparts, specifically in temperatures ranging from 10 C to -20 C.
The Oxford study is really good. But I can't say the same about this article.
A COP of ~2 is not great for a heat pump, calling this a triumph is really weird. But from a journalist saying that a COP above 1 means the heat pump "creates energy", I am not sure I should have expected more.
But what's great is that this COP of 2, while bad, is not catastrophic. That's still in territory where gas boilers are more cost efficient that a heat pump, but unless you are living in a place that is consistently under -10C for several months, then a heat pump has overall lower running costs than a gas boiler. And you are starting to hit pretty northern territories with this.
What's important is also to be able to store heat during the day so that the heat pump runs at its most efficient time. But that can unfortunately coincide with the higher consumption time, so the timing needs to be adjusted properly to avoid using it during consumption peaks.
Maybe someone can help me answer this question as I'll be replacing my old furnace in the near future and am curious about the heat pump systems.
Studies like this are only looking at efficiency and not total energy usage or heating capacity so how do you compare apples to apples? A high efficiency forced-air furnace using natural gas is something like 95% efficient, and a heat pump can be something like 150%-200% (because you're moving the heat instead of creating it), but the total output capacity matters as well as the efficiency of generating and transmitting the electricity. Also, I don't think the power needed to run the fans gets factored in from what I can tell and I expect a heat pump system to need fans running far more often and for longer. Since heat is constantly being lost to outside then whichever can work faster might have an advantage keeping ahead of that entropy too...
I'm living in a climate considered "extreme cold" in this study btw. Best I've been able to figure out, a gas furnace is still much cheaper to install/operate (it's pretty cheap here) but is also still be better for the environment as my electricity tends to be generated primarily from natural gas and coal (at an efficiency lower than a natural gas furnace does).
They're only two to three times more efficient if they aren't frozen solid. Don't know how it works in Canada, but my mini-split heat pump can't handle a week of 10F let alone -20 C - sure it will put out some heat, but it absolutely needs to be supplemented with my wood stove. And I live in the South. Maybe there's some new high tech heat pumps that cost a fortune and don't freeze over in the insane temps of the great white north? EDIT: hey, folks, how about actually responding instead of downvoting me? If I don't have a clue, please enlighten me. Fuckers.
I don't know that we really needed a study for this. You can find the COP vs temp vs capacity curves for every heat pump out there. This will tell you exactly how many BTUs of heat the pump will produce given a watt of electricity input. I guess they were just validating that the curves were accurate?
A/C guy who's the son of an A/C guy here. Heat pumps lose efficiency the colder it gets. I wouldn't bother with one if you're in a northern climate. Lower midwest, you might be able to save money with a heat pump over natural gas, but it will depend heavily on the cost of the respective energy. For me, in the central US, we have great prices on gas and somewhat crappy prices on electricity (vs most surrounding regions) and it's definitely cheaper for me to stick with gas heat.
That's great, but fossil fuels are often available in the event of a power outage, and that can save lives during a winter storm. Availability is just as important as efficiency, and until we can make our power grid more resilient, we need to factor that in.