Ok fair enough so you are saying for example inverter and solar without batteries and switch back to grid when solar is insufficient ? That's possible but you need a 5kw inverter and those use about 70wh all the time, so an extra 1.7kwh a day.
Heck if I know
Your heat pumps would have kept up. Whatever you have is not standard in "builder grade" construction in Texas, nor are people "cold weather performance" concerned about HVAC. Most people have no clue.
It's actually the cold that's gotten people killed. We "sometimes" have brownouts for high HVAC use, but I think it's a lot easier to predict the need for capacity.
I think ,in Texas,more people die of heat ,than they do of cold.
I believe that, but we have about 360 days of heat and 5 days of cold, so it's gonna work out that way.
You can use a cheap inverter and cheap bypass mechanism to just run your base loads. The battery doesn't need to be sized for additional run time, just to stabilize the inverter as a cloud front comes through. You size the bank at about 2kWh(nominal)/kW PV; AGM batteries (even used) can do the job.
At 5 degrees out does use some resistive heat but the COP is still 1.8 so not purely resistive.
It depends on the brand and model. The ones I have are 100% efficient down to 5 degrees F. I think it was @SolarScott who did a video of his at something like 4 degrees and it was still toasty in the house. The standard heat pumps though, are only good down to about 30 degrees.
Mine don't even have heat strips installed. But no, they are not builder grade. I think a lot more people are concerned about cold weather after the last few winters. But to each his own.
The sun is high in the sky in summer and it's only 400sq ft of windows who needs shading? ??You can use a cheap inverter and cheap bypass mechanism to just run your base loads. The battery doesn't need to be sized for additional run time, just to stabilize the inverter as a cloud front comes through. You size the bank at about 2kWh(nominal)/kW PV; AGM batteries (even used) can do the job.
But, your best payback is likely summer awnings to shade the house more.
I can't remember an outage longer than an hour since I've lived here but if we some that outages will become more common then the backup system you described would be very advantageous, but that would be a fairly big assumption
I have a ground source heat pump and it does not care what the outside temp is as the water is a constant 72° f with a COP of 4 the newer units have a higher cop.
Ooh I heard those can cost 30-60k installed?
I installed mine over 20 years ago and now your price would be about right the unit itself is about 3k now it is the water loop that is expensive I have 4 200ft vertical wells for the loop.
As far as water goes , I bought. 350 gallon potable plastic water tank…10 years ago … it’s made to fit snuggly in the back of a USA standard pick up truck…weighs about 2800 lbs full. put a 10 dollar hose tap in the side near the bottom…bought a 89.00 Shureflo 12 volt water pump…and some white hose.. hook it to a tap on the cabin or the RV…yer done ..!
