Ductless cooling and heating. Where to start?

Zipper13 · May 2020

Our 1920's home has a ~15'x~15' family room addition with vaulted ceilings built in the late 90's.
The house is heated with steam but this room is electric baseboard. The electric baseboards are OK and do heat the room fine, but they're not the cheapest to run. The addition is over a crawlspace and with door and window placement, I don't see a viable path to add a useful radiator to the room at least not not in a financially responsible way.

This room also gets pretty warm in the summer and due it being all casement windows, we cant get a window AC or a portable AC in there.

We're more motivated to explore ductless AC in there now that we're working from home all summer.
And we're also thinking that a mini split (I think?) could offer some slight efficiency on heating in winter or in shoulder seasons. We keep heat fairly low in that room but it still adds up without really being comfortable in the winter. I expect the savings on heating will not really ever pay for it self over its life, but could make the cost of adding AC there more palatable.

So as someone trying to be an informed consumer:

Are there particular red flags to keep an ear out for as we shop around for quotes?

Are there particular brands to request or to watch out for?

Perhaps most importantly, is there someone you trust and recommend who works the North Shore area / Greater Boston?

STEVEusaPA · May 2020

I'm sure you can find a Wallie that can help you.
Step 1. Heat loss, heating and cooling load. If you can insulate under the crawl space before, even better.
Newest mini splits can get down pretty low and I'd bet they would take care of the heating. Might not keep the room at 70° on the coldest night, but you probably get solar gain during the day.
If sized right, it'll do the cooling just fine.
Ceiling fan may help in both modes too.
Definitely more efficient than straight electric baseboard. You'll probably find you don't need them at all, but if you like back up and redundancy, keep them there, maybe set the t-stat for 45°.
You could even throw a small gas/propane/electric fireplace in there for ambiance and heat boost. Just make sure it's vented, no indoor bbq grills

EBEBRATT-Ed · May 2020

@Zipper13

They used to make casement window units I am sure they still do.

That being said, you might investigate a hot water loop off the steam boiler and get rid of the electric heat.

The best choice might be a ductless mini split heat pump. You will get AC and will save $$ on heat will probably work fine and if you need the electric baseboard when it gets below 20 deg so be it

GW · May 2020

I’d say just get some quotes, then you’ll see some hvac guys and gals will discuss different things- that’s how you learn. I was on a sales call this week, the wife was quite informed. Out of the hundreds of systems we’ve installed, no one has ever asked me about the material we use to drain the condensation. She’s like, “ I don’t want that cheap corroborated stuff”. I was like “ wow you’re the first person ever that brought up that word to me, you’ve done your homework

weil_fail · May 2020

single room? how handy are you? a single room mini-split with a crawl space is about as easy of an install as you can get. in the realm of doing it yourself, if you're handy. people tend to not recommend that because you don't get a warranty and you still need someone to pull the initial vacuum (or you have to buy a vacuum pump and flaring tool), and someone to do the electrical to keep it all code. the counter-argument to that is: that who needs a warranty when it costs 1/5th as much to install yourself vs a professional? you can just scrap it in 5 years and install another one if there is an unrepairable failure.

there are floor mount mini splits that could make for a very easy bottom-access installation (see link at the bottom of this post)

you will want a unit that can produce heat at low temperatures since you're in Boston. Mitsubishi uses a technique that gives better performance and efficiency at low temperatures than most, but they're more expensive if you buy them wholesale since mitsubishi does not like DIYers installing their units.

I've heard of people installing everything themselves then having a pro do the electrical and vacuum, which can still get you the factory warranty. I'm not sure how many companies are interested in doing that, though. you could ask around.

if you go with a mini-split, I would consider keeping the electric baseboard for the first year to see how the mini-split performs on the coldest days.

https://www.acwholesalers.com/cooling/floor-mounted-ductless-mini-splits.html?sort_value=&displaynum=0&spec_options_id[1228][]=-13&spec_options_id[1228][]=-15&spec_options_id[164][w1]=&spec_options_id[164][w2]=&spec_options_id[158][w1]=&spec_options_id[158][w2]=&spec_options_id[2][w1]=&spec_options_id[2][w2]=

here is another option if you don't mind going through the wall for a wall-mount:
https://www.homedepot.com/b/Heating-Venting-Cooling-Ductless-Mini-Splits/-13/-15-F/-22/Single-Zone/N-5yc1vZc4m1Z1z0y63vZ1z19b7pZ1z19b7zZ1z19b84?NCNI-5&experienceName=default&storeSelection=2579,2503,2501,2584,2505

weil_fail · May 2020

sounds like a great use-case for a mini-split. they make some that work well at low temperatures (below zero). might want to keep the electric baseboard for the first year at least to see how it works at very low temps. definitely get quotes. I'm a huge fan of mini-splits.

pecmsg · May 2020

Ducted Minis are an option in the crawl space.

Can you get a steam coil in there?

Zipper13 · May 2020

Thanks for the comments.

I re-insulated the floor over the crawlspace last summer and found a slight improvement the past winter. the crawlspace itself extremely low, is passively vented and unconditioned so I don't see using that space for any equipment.

I've tried a few online heat loss calculators so that I can have something to compare against any proposals, but the numbers have been all over the place. is there a free heat loss calculator that you recommend?

I've seen casement window AC's out there, but all require the pane to be removed altogether and to fabricate something to take up the rest of the window space. security, aesthetics, and noise of such units are all mild to moderate concerns on their own, but together they make the idea of a casement window AC unappealing.

I'm fairly handy, but I'm also one who learns by making mistakes along the way. For a purchase of this size, I'd prefer to pay someone who isn't learning as he goes like I would have to do. sure, I get the impression that I could do this, but I also want it done in a day not over the course of a week while I order new parts I didn't know about or broke along the way.

I understand that with this, as with most cases I've seen on the wall, the biggest thing is the quality of the installer rather than the brand. I'll have some quotes done, but I find it very tough to vet contractors. Google reviews are helpful, but you never know if people are rating the personality/price/brand/expertise/etc. I imagine most customers just care that it works and its shiny - but are customers confident in the sizing of the system, the quality of the electrical work, properly insulated? the more time I spend here, the more I fear that qualified contractors are rare and hard to find.

TAG · May 2020

I extended a small sitting area by building a 15 x 22 single story addition. Foundation/slab w/ Warmboard radiant. Steep roof with scissor truss for a cathedral ceiling. Tucked a 12k Mitsubishi hyper mini up on the old wall of the house -- so it blows into the new room and you can't see it unless you are in the room looking back. Works great -- lots of windows in the room and a door. The heat from it is amazing -- even in single digits. We used it for heat most of the first winter before the Warmboard was hooked up ... it's also uses early late in the season when the radiant is off

Ductless cooling and heating. Where to start?

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