I think you underestimate what it takes to heat an older structure in the north. 7kw is pretty common for whole-home retrofits. Enough to run that all night in winter during an extended cloudy spell means a lot more panels and a lot more storage.
Are you suggesting a 7kw heat pump, or 7,000kwh/m highest hearing load? Because the former would already come out to about 2.5k kwh assuming a 12h duty cycle for 30 days, while the latter would cost over a thousand dollars a month to run at average US electricity prices during the month of highest load.
For reference the typical heat pump in the typical amarican single family house consumes 5.4k kwh in an entire year.
and it says “Based on an EnergySage analysis of a Department of Energy database, a typical heat pump in a typical home uses 5,475 kilowatt hours (kWh) per year”
but then treated it as meaning a “about 5½kwh” instead of 5475kwh.
The two are very different numbers, and most heat pumps in the US are currently installed in warmer locations, so you can expect utilization in colder places to be appreciably higher.
A heat pump won’t be running at peak output all year long, but during winter in the north, it’s likely to do so every night for a week at some point.
A $1000/month heating bill isn’t that rare in some parts of the US in winter.
In most (sane) numbering systems, you can use a k in place of thousands, m in the place of millions, etc. Becuse all the numbers around the scale of energy use involving the entire monthly power consumption use of a heat pump in a cold climate as well as solar production and storage needed are in thousands, you will note I wrote all the relevant numbers with the abbreviation k, so 5,475 kwh is equivalent to 5.4k kwh.
Admittedly 5.4 mwh would have been more clear, but because megawatt hours is less commonly used and would involved useing two diffrent units next to each other I used thousands of the same unit for consistency. Please go back and re-read all of my comments with this new knowledge in mind.
Yes, many heat pumps are installed in warmer climates, though that is changing, but blowing through the entire yearly national average in three weeks and then doing it again is lot of power for a climate contentious and thusly presumably well insulated off grid modern house to use. (Also, if we go back to what this conversation is about, the original commenter gave no indication that they were in a very cold climate with thousand dollar a month heating costs in the first place.)
We are literally talking about whether it is practically possible for a major renovation to a lifelong dream home. If they are in love with an old poorly built and insulated home in a very cold area then yes, in a few decades when this do this they will have to have it insulated to at least modern standards and of doing so it’s likely worth it to go to far better, but that is a very long way from your position that no one could even think about it being feasible for anyone in a few decades.
Can I be sure what will happen decades from now? No, but I can say for sure that at the moment, if you want to add insulation to an existing older structure, and not do a complete rebuild, you end up with a structure which isn’t anywhere near as well insulated as a newly-built structure designed for efficiency.
I think you underestimate what it takes to heat an older structure in the north. 7kw is pretty common for whole-home retrofits. Enough to run that all night in winter during an extended cloudy spell means a lot more panels and a lot more storage.
Are you suggesting a 7kw heat pump, or 7,000kwh/m highest hearing load? Because the former would already come out to about 2.5k kwh assuming a 12h duty cycle for 30 days, while the latter would cost over a thousand dollars a month to run at average US electricity prices during the month of highest load.
For reference the typical heat pump in the typical amarican single family house consumes 5.4k kwh in an entire year.
I think you googled, took the first result, which was:
https://www.energysage.com/electricity/house-watts/how-many-watts-does-an-air-source-heat-pump-use/
and it says “Based on an EnergySage analysis of a Department of Energy database, a typical heat pump in a typical home uses 5,475 kilowatt hours (kWh) per year”
but then treated it as meaning a “about 5½kwh” instead of 5475kwh.
The two are very different numbers, and most heat pumps in the US are currently installed in warmer locations, so you can expect utilization in colder places to be appreciably higher.
A heat pump won’t be running at peak output all year long, but during winter in the north, it’s likely to do so every night for a week at some point.
A $1000/month heating bill isn’t that rare in some parts of the US in winter.
In most (sane) numbering systems, you can use a k in place of thousands, m in the place of millions, etc. Becuse all the numbers around the scale of energy use involving the entire monthly power consumption use of a heat pump in a cold climate as well as solar production and storage needed are in thousands, you will note I wrote all the relevant numbers with the abbreviation k, so 5,475 kwh is equivalent to 5.4k kwh.
Admittedly 5.4 mwh would have been more clear, but because megawatt hours is less commonly used and would involved useing two diffrent units next to each other I used thousands of the same unit for consistency. Please go back and re-read all of my comments with this new knowledge in mind.
Yes, many heat pumps are installed in warmer climates, though that is changing, but blowing through the entire yearly national average in three weeks and then doing it again is lot of power for a climate contentious and thusly presumably well insulated off grid modern house to use. (Also, if we go back to what this conversation is about, the original commenter gave no indication that they were in a very cold climate with thousand dollar a month heating costs in the first place.)
For a modern well-insulated structure, sure. But a lot of US housing was built without insulation. And people live in it and would prefer to retrofit.
We are literally talking about whether it is practically possible for a major renovation to a lifelong dream home. If they are in love with an old poorly built and insulated home in a very cold area then yes, in a few decades when this do this they will have to have it insulated to at least modern standards and of doing so it’s likely worth it to go to far better, but that is a very long way from your position that no one could even think about it being feasible for anyone in a few decades.
Can I be sure what will happen decades from now? No, but I can say for sure that at the moment, if you want to add insulation to an existing older structure, and not do a complete rebuild, you end up with a structure which isn’t anywhere near as well insulated as a newly-built structure designed for efficiency.
Again, where are you getting the idea that the original commenter has to be talking about being set on a old, poorly insulated home?
That’s pretty much what most retrofits in the US look like.