Furnace/ACvs.heat pump?

[Innovate1]

Familiar with Furnace/AC systems and that's what I have in the house. 90+ condensing furnace. Figured I would do the same in the shop (detached garage). But I have seen a lot on here about heat pumps and the HVAC guy suggested it as a option - they handle Mitsibishi and they have a hyper heat system that needs no back up resistance heat. They are going to give me a price both ways.

He asked about power wondering if I had enough but have a 100A panel and he said it was 30A max so no issue there.

Building is 30 x 40 with a 15 x 16 walled off section that I plan to heat and cool all the time. May turn down the rest occasionally.

He said probably a 2 head or 3 head system.

What do I need to know about heat pumps? How does the cost of running the different systems compare?

Is there a minimum inside temp like on a furnace to prevent condensation in the primary heat exchanger? Or can I turn down the heat pump lower when I am not using the building for long periods?

 

[danski0224]

You have to look at the specs to determine BTU output at minimum operating temperature. How many BTU does your space need? Is the unit sized right?

Then, does the unit minimum operating temperature align with your location conditions.

The fancy multi mini splits MUST be installed to manufacturer spec.

 

[nadogail]

The short answer is "It Depends".

A thing to consider is the cost of energy. Solar electricity, once installed has a very low cost per KWH.

A waste oil burner, with sufficient free fuel, might be the most cost effective source of heat.

Waste heat from a manufacturing operation often can be used to warm a shop economically

 

[finn]

I have three Mitsubishi units, and like them. Two are Hyper heat, but I wouldn’t do without a conventional furnace or boiler in my area.

One thing to consider, given the current virus pandemic, is that the mini splits have pretty marginal air filtration capabilities, and pretty much rely on recirculating air that’s already in the room.

There are a couple of studies going on to investigate the roll mini splits had on virus contamination, given the popularity of the units in China, the rest of Asia, and Europe.

We, here, are late adaptors of the technology compared to the rest of the world.

Not saying there is a relationship, just that there are studies going on.

 

[Innovate1]

Your area gets a lot colder than here. Even here the hyper heat units lose a lot of capacity at low temps. I dont care if the inside temp drops a bit at record lows as long as it doesn't freeze. I need to look at the unit specs.

 

[Innovate1]

Talked to another contractor today. He proposed the attached layout with the outdoor unit where the AC is marked. Said the fan would blow air 35 ft and the unit by the bathroom would cover that area ok. Being used to a ducted system with ducts to all the corners this seems optimistic. I don't need the whole building to be exactly the same temp but are they really that good without ducts? I know the performance, BTU and efficiency wise is good. Just wondering about air distribution.