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> Random anecdote: in New Jersey installing a Mitsubishi hyper-heat heat-pump in a 8 room house (4 bedroom + 2 bathroom + living room + kitchen) is much more ex

> Random anecdote: in New Jersey installing a Mitsubishi hyper-heat heat-pump in a 8 room house (4 bedroom + 2 bathroom + living room + kitchen) is much more expensive than running hot water baseboard in all rooms. And with most heat pumps you can usually only zone 4-6 heads per compressor, so you'd need two compressors. A single compressor is probably pulling 50 amps alone, so you'd need 100 amps available usually for your breakers. For reference, a normal house usually 100 amps dedicated for the entire house, not just HVAC. Drastic upgrades in electric infrastructure will be required. No, no, and no. First of all, you would never put a head in each of these rooms. The minimum head sizes of Mitsubishi (and all other) mini splits is well beyond the heating or cooling loads of an individual room. Anyone who tries to sell a head per room is a charlatan and has never run a Manual J load calculation in their life. Furthermore, if your four bedroom house requires 100 amps to heat it with a heat pump, you should have put money into air sealing and insulating it, rather than installing heat pumps. This would impute a 160,000 Btu/h heat load, which is astronomical in New Jersey. (I know this because I live here, and design these systems.)

endisneigh 5y ago
I'm not sure how you can say that without knowing the heat loss for every room. With a wall mounted unit and closed doors there's not really any alternative. My entire example is meant to just be an example. In reality you'd use a ducted split system, not 8 heads. Anyway, are you claiming installing a split system is cheaper than installing a Burnham boiler? The point of the post is to say that boilers/furnaces are much cheaper to install in order to heat your entire house.
- insaneirish 5y ago
  > I'm not sure how you can say that without knowing the heat loss for every room. I can say it because houses are fairly typical and if the heat loss for a room is greater than the minimum head size for a minisplit, the room probably needs some work before you should be putting a minisplit in it. This is all just math, and 6,000 Btu/h (the minimum head size) happens to actually be a lot of heating for any normal room.
  - endisneigh 5y ago
    yes but a hyper heat can modulate down to 1.6k btu/hr, so you still would just put that in every room. (as long as total for condenser is 6k btu/hr, so 4 x 1.5k btu/hr) but again, that wasn't really the point anyway.
- insaneirish 5y ago
  > Anyway, are you claiming installing a split system is cheaper than installing a Burnham boiler? A boiler alone does not a hydronic system make. Hydronic systems are expensive, all in (piping, emitters/radiators, circulator pumps). > The point of the post is to say that boilers/furnaces are much cheaper to install in order to heat your entire house. No new house in New Jersey is getting built without air conditioning. If you're already installing ducting and an air handler, you might as well pay the marginal increase to get a heat pump instead of a cooling only outdoor unit.

endisneigh 5y ago

I'm not sure how you can say that without knowing the heat loss for every room. With a wall mounted unit and closed doors there's not really any alternative. My entire example is meant to just be an example. In reality you'd use a ducted split system, not 8 heads. Anyway, are you claiming installing a split system is cheaper than installing a Burnham boiler? The point of the post is to say that boilers/furnaces are much cheaper to install in order to heat your entire house.

insaneirish 5y ago
> I'm not sure how you can say that without knowing the heat loss for every room. I can say it because houses are fairly typical and if the heat loss for a room is greater than the minimum head size for a minisplit, the room probably needs some work before you should be putting a minisplit in it. This is all just math, and 6,000 Btu/h (the minimum head size) happens to actually be a lot of heating for any normal room.
- endisneigh 5y ago
  yes but a hyper heat can modulate down to 1.6k btu/hr, so you still would just put that in every room. (as long as total for condenser is 6k btu/hr, so 4 x 1.5k btu/hr) but again, that wasn't really the point anyway.
insaneirish 5y ago
> Anyway, are you claiming installing a split system is cheaper than installing a Burnham boiler? A boiler alone does not a hydronic system make. Hydronic systems are expensive, all in (piping, emitters/radiators, circulator pumps). > The point of the post is to say that boilers/furnaces are much cheaper to install in order to heat your entire house. No new house in New Jersey is getting built without air conditioning. If you're already installing ducting and an air handler, you might as well pay the marginal increase to get a heat pump instead of a cooling only outdoor unit.