Air exchange HRVs are quite common here in the Netherlands. Not exactly ubiquitous, but common enough that you can find them in most recently built apartments at the very least. If you're going to have mechanical ventilation installed, you may as well save a buck in the long run on the heat loss.
There's only so much temperature gradient these setups can handle economically, and it's quite possible that the hot LA summers combined with the cool AC air are too much for such an installation not to leak energy at an unacceptable rate.
Then again, just like with ACs that also serve as heat pumps, it could just be a matter of not enough people (or professionals) knowing about these installations to make it viable to build a business around them.
Type in HRV system in to your preferred search provider and hit the shopping tab.
Here in Australia they range from about 1500 Antipodean Dineros for a single room through-wall mounted systems, and around 5500 upward for a centralised unit. Plus installation costs, but HVAC install is one of my paid activities, so I mostly don’t pay that part.
NB heat pump is a more accurate term for refrigeration type air conditioners, as in cooling mode they’re ‘pumping’ the heat out of the inside environment and rejecting it outside.
> I can't find anyone to install one in Los Angeles.
If you call a random HVAC company, they may not want to deal with "fussy clients" that want something "fancy" like an HRV/ERV. Best to look at folks that perhaps try to adhere to building science more. A quick search for the LA area:
They have been required by code in all new houses in Minnesota for about 25 years.
I'm sure CA requires them too. Though in older houses they are a waste of money as your house already leaks much air. These are a good thing if you have a well sealed house, but older houses universally are not sealed that well and so they won't give you anything.
There's only so much temperature gradient these setups can handle economically, and it's quite possible that the hot LA summers combined with the cool AC air are too much for such an installation not to leak energy at an unacceptable rate.
Then again, just like with ACs that also serve as heat pumps, it could just be a matter of not enough people (or professionals) knowing about these installations to make it viable to build a business around them.