HVAC questions

[yanmars]

I need to install HVAC in a 2 story building. At this time the walls and floors are pretty much open. My only real options are propane or electric for the most part.
Have read some about the mini splits and comb heat pumps. Some of the combo heat pumps say they are quite efficient, SEER values from 16 to 27. They advertise the heat pumps now work to -20F. They advertise they would save heating/cooling costs of about 25 % over other systems in smaller units and no need necessarily for ductwork. I know one can promise anything. Just hoping some have had real world experiences with the newer high efficiency units.
My daughter has an older mini split system and does not like it for an add on room. My neighbor has a somewhat newer unit and likes it. Thoughts?

 

[radios1]

I'd go with geothermal, as the ground is much warmer than the air!. and for supplemental heat, propane instead of the very costly electric!..

 

[user.69169]

All depends on where you putting machinery.

What work on Longgggg Island not work so good in Arizona.

 

[yanmars]

I should have mentioned I live in western Ohio. The ground is on the 1/4 section farm so I would have room for geothermal if I would decide to go that way. I thought that was quite a bit more expensive however. Just in the initial stages of asking. Glad for everyone's input.

 

[3Ts]

I have a mini-split in our cabin that we installed ourselves 6 years ago. The biggest concern I had about them was whether they would produce warm air or whether they would blow air only 1* above ambient which would make it feel cold to me. Until this last week here in Texas it's only had to deal with temps down to 17* and it's done fine keeping the cabin warm (70*) and the air is warm enough I'll go stand under it when I feel cold. This week the temps got down to 0* and it is still keeping the cabin at 70* with warm air. We like it. The cabin is 36' long and is a single room with the only partition being the bathroom and it has no problem circulating the air. The various spots in the room range from 69* to 71* which may be the tolerance of that particular sensor. If you have multiple rooms, your results may be different.

 

[user.69169]

1st I think you asking in wrong place.
Quick search give me dis. Is Geothermal Worth It in My Region? | GeoExchange(R) Forum
Got bunch other hits I didn't click to look.

BIG question, how long you gonna live der? Long time put system makes you happiest.

Geothermal good system IF and only IF you understand and can install yourself. You need contractor you bleed thru eyeballs and get crap system.

You in Ohio, energy cost going UP. No more burning coal soon and you live on top of coal pile. Even burning gas gonna go away in few years so /electric cost way more thanks to Greeny buyin politician. Geothermal totally electric so gonna cost you to run. Propane price probably stay low unless China need plastic pellets.

Walls & ceilings open give you chance to install proper duct now. Use fiberglass and mylar duct wid fiberglass cover and cut duct loss. Can even install proper duct system to blow cold air near ceiling from AC exchanger. Cheap to do now and best energy efficiency you gonna live der long time.

Minisplit big advertising, but is a lifestyle too. Some people like, some hate. Similar unit is hi velosity ducting from central exchanger. Exchanger can be pretty much any fuel. Again, you need contractor you gonna bleed.

You got water available cheap think on wet roof evaporation cooling or even heat harvester in attic. Either one cheaper to run den conventional AC in summer. Power vent attic space to minimize AC load too. Ohio cool at night, small fan pull accumulated heat out of attic and insulation cheap.

Make up chart of benefits and desires den pick. Whole lot of choices to be made den fuel.

 

[ssamsamm]

I'd go with geothermal, as the ground is much warmer than the air!. Also chekc ut this page for some info on how to get loan with no credit check and for supplemental heat, propane instead of the very costly electric!..

Isn't it a little bit costly?

 

[MoKelly]

Isn't it a little bit costly?

Yes. Very. I’ve read the payback in lower future energy costs is approx. 10 years.

MoKelly

 

[JM7500]

An option similar to a mini-split is a Variable Refrigerant Volume (VRV) system. It has one outdoor condensing unit with multiple indoor units, which can be controlled independently. These systems are very efficient, but not as efficient as ground source. However, the cost of a VRV system is considerable less than ground source. Even with propane heaters as a backup, it's cheaper than ground source. They are very common in Europe and Asia and gaining popularity in this country.

 

[dodge man]

The key to geothermal is what is the government incentives? We have had ours roughly 8 years. At that time we wrote a big chunk of the cost, like roughly 30%. I think it’s 26% now. So for a 20k system you would write $5200 off your taxes. As I recall, that’s off your taxes not your income, so a 20k system costs you more like $14800. I also pay less for the electricity the geothermal uses but that probably depends on your utility. For us the payback was more like 5 years.

It also depends on what’s available to you, I live outside of town so no natural gas. Without the tax incentives geothermal doesn’t look so good if you have natural gas available. With the incentives it looks good.

 

[chim]

We have around 2,700SF two story with 6" outside walls and extra attic insulation. The 95% efficient 100MBTU Trane LP gas furnace keeps us comfy and since we buried a 1,000 gallon tank we can buy when the price is down. Generally costs us about $500 per heating season. Wifey watches the prices and buys when it's close to $1.00 per gallon. We're coming to the end of the heating season and there's 35% left in the tank. When filled, it is about 85% full.

Cooling is with a DX coil in the furnace plenum. Love this setup.

 

[radios1]

Isn't it a little bit costly?

if you can dig the trench or holes, not much, that's where the cost is.. some areas you can get away with just a deep trench, others you'll need a well drilling rig to get down deep..

 

[not2old]

We have an abundance of water here, only 22' down, which makes an open loop geothermal system even more efficient without the cost of installing the ground loop. Only once have we experienced colder than -25C for a few days and it didn't seem to make any difference to our heat. Another bonus is that air conditioning is even less expensive to run. My system recovers heat for the domestic hot water as well. I think it's the way to go if you have the water available.

 

[radios1]

100MBTU is enough for a large palace, I'm sure you meant 100KBTU..

 

[chim]

Maybe somewhere, but the schedules I'm accustomed to seeing on drawings follows this:

BTU to MBTU Conversion - Convert BTU to MBTU (BTU to mbtu) - Energy Conversion

www.theunitconverter.com

 

[JM7500]

1 ton = 12,000 btu/hr. 1 ton can cool from 300-750 square feet. It's worse to oversize your air conditioner than underside. If the unit is too large, the unit will short cycle-while the air will be at a good temperature, the unit doesn't have time to remove the moisture from the air and your humidity will be high. Humidity plays as part of being comfortable as the temperature.

 

[Handloader109]

I just installed a small mini split from denville 18kbtu unit for my basement. I work down there and it gets cold. Our main HVAC wasnt really set up for doing more than keeping the basement from freezing as no ducts outside area near the inside air handle. And the unit is really undersized for the house. I looked at a bunch of options, and as we are down to electricity or propane, I went with this mini split. Drilled through my 8 inch pored concrete wall, and pored a pad. installed, checked it out for leaks and it works. Very well I might add. It is rated at a -20f still to provide heat. It has warmed up, but I cranked it up at 45 outside with it being 60f in the basement and it put out 95f air.

 

[yanmars]

Good to hear.

 

[Frankenkubota]

I've been reading about how heat pumps work for a long time.

I know they harvest the heat from the outside air, even when it "cold" outside but..........

Seems to me most the heat is generated when the gas is compressed?

 

[dodge man]

Freon goes through a phase change in heat pumps, ac units, dehumidifiers, and geothermal units. When things go through a phase change they release a lot of energy. In the case of Freon a gas to a liquid, and a liquid to a gas. You compress Freon it gets hot, you blow air over it, you get heat in your house. In that process it gets cold, you put that cold outside and blow air over that is warmer, compress it back to a liquid and start the process over again. During the summer the process flip flops and the heat goes outside and the cold inside.