advice on heating and cooling a sun room

hot_rod

would be a good place to start.

An un-insulated concrete slab may present an uncomfortable winter time space, regardless of how much hot air you blow against 'er.

Insulated window shades could make a huge difference in losses also.

Any way to install some slab edge insulation?

hr

Bill_55

advice on heating and cooling a sun room

Here's the situation:

In northern Delaware. Have a sun room that's being renovated. It's about twelve feet by twenty feet. On a standard concrete slab-- no insulation. Walls and ceiling are insulated. One long wall is actually the exterior wall of the house. The other three will have double hung windows... double pane insulated low E glass. (These will replace single pane awning windows.) There are two large paddle fans on the porch.

The house has hot air heat and central air. There's no way to get any ductwork out to the porch. Got an estimate on a mini split system-- heat pump-- Mitsubishi Mr. Slim. There is no backup electric resistance heat in the Mr. Slim system and the literature on-line clearly indicates that once the outside temp is below 17 degrees, there's no more heat. The contractor didn't seem to think that was a big deal when I asked about it but realistically, we CAN get several weeks of nights in the teens and even a week or two of daytime highs in the teens.

Do other mini split systems have backup electric resistance heat?

What about a packaged terminal AC unit with heat pump and electric backup? The PTAC is alot less costly than the mini split. I know it's not as efficient or as quiet as the mini split.

I was thinking about trying the PTAC, assuming that it will probably do a good job cooling but possibly not heating. The main heating and AC system as well as the domestic hot water heater will need to be replaced in the next couple of years. Thought that if we need more heat in the sun room than the PTAC can supply, maybe at that time we could go with a hydro air system and put a loop of hot water baseboard in the sun room. We could get copper tubing or pex out to the sun porch..

I don't necessarily want the cheapest solution but rather one that will work well for all seasons. Doesn't seem to be much point in putting in thousands of dollars in windows and then still not be able to use the room all year round.

I would welcome any advice or suggestions. Thanks in advance.

Wayco Wayne_2

Bill

I recommend staying with the ductless heat pump. If you need heat during the extreme temp times you can put a portable electric heater out there. If you want you can install some more permament electric baseboards as supplemental heat. The PTAC units are dogs. They make a big hole in your wall that leaks infiltration. They are noisy and not efficient. WW

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Jack

Mini Split

I would use the Fujitsu mini split (because they are more efficient, less money and I represent them). I don't have the book handy to check how often it gets below 17, but we have a 24RLXQ model that will go down to zero F with a minus 13F cut-out. If another model is chosen, be careful as the lower limits vary by model . Some go to 5 some 14. As a backup I'd recommend the Air-Share by Tjernlund. It is a transfer fan which could pump houose heat out to the other room. Only 75 cfm but effective and short money. www.fujitsugeneral.com www.tjernlund.com

WV EGBERT_2

Hyper Heat Pump

Mitsubishi Mr. Slim has a model 36,000 btu H2i that will maintain 100% of its capacity down to 0* and will work at 75% of capacity down to -13*.

Pricey though.



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Bob Bona_4

Jack

could you tell us in your own words about the inverter technology Fujitsu has?

I have put in many of the 21 SEER cool only, but have shied away from HP applications. How do they manage to produce heat in such low ambients? I can think of at least one reason the heads don't have heat strips