HVAC for a basement layout

I installed a ductless split system, it was a simple install and works well for my basement.

lehighline: I don’t know what region of the country you live in. But if possible, choose a finished basement that’s already “HVACed.” A nice basement room is all the “blank slate” you need.

Then you can concentrate on putting your time and money into the layout without having to spruce up what’s going to be the train room. You could start on the layout right off the bat. 😉

From your profile you are in PA, so is John so a simple DFS (Duct free system) IE: Mini Split would be fine.

I do HVAC in Kansas. Basements are tricky even with a unfinished basement they should’ve already ran ducts for the basement how ever at least here the basement is almost always cooler, the only real way to dehumidify is with a dedicated dehumidifier, DFS can dehumidify but you will that will drop the efficiency of that system. I can go more in-depth if you want but I’ll stop there.

At the end of the day basements have a different load than the rest of the house and that typically makes it hard for a system doing a main floor and the basement to keep an even temperature. It all depends on duct sizing and a lot of people will cut it as small as they can to just get by.

While the mini-split claims to have a dehumidification function, I find that a separate dehumidifier is far superior.  The mini-split ends up air conditioning to perform the dehumidification function, and frequently it's cold enough in the basement.  The separate dehumidifier doesn't do any cooling, it actually adds a little heat.  Most of the time that works better for my location.

Mine ended up being a bargain since we were doing a large loft on the 3rd floor with the mini-split, the outside unit handles up to four inside units, so for a couple grand I just added a second indoor unit.

Have mini split system with four units on first floor and one in basement. One unit outside handles the five indoor units. Had it installed as have hot water baseboard on first floor and needed ac on first floor. Have forced air with ac on second floor. Would have been a real pain to run ducts. Mini split is a really great system as you just turn on the unit in the room you want heat or cool. In the basement train room use it most of the time for heat, but also use the ac from time to time. Use a stand alone dehumidifier as it seems to work a little better as basements get  humid in Chicago area.

By me, I believe it a no-no to connect your HVAC to your garage, presumably because fumes from the garage could spread to the house.  Whatever you do, be careful about keeping your good air separated from your bad air.

@Long Hair posted:

By me, I believe it a no-no to connect your HVAC to your garage, presumably because fumes from the garage could spread to the house.  Whatever you do, be careful about keeping your good air separated from your bad air.

Who suggested connecting the HVAC to the garage?

He's looking at houses.  In my house, the garage and basement are very connected,

A/C and heat in garage from the house HVAC is very common and yes you could get fumes but you should never run the car with garage door closed which diminishes the fume issue to be almost non existent.

I my garage in SC I installed a mini space system. It’s great in the summer and the other night I switched over to heat and the area was warm. When I lived in PA I installed a propane wall mounted heater. That was great for the winter and summer months all I had was a dehumidifier. No AC it wasn’t needed. If you have questions call me. You still have my number.

Chris, I had a similar situation and I went with the mini split. I’m in mid state PA and haven’t had a need for a dehumidifier. BTW go for extra outlets in the walls and, if possible, the floor.

Jay

We have a Carrier mini split in the garage.  It is a large two car and insulated.  It keeps the garage comfortable all year round.  The other good mini split brand is Mitsubishi.  I think you would be fine with either so long as the installer is a professional.

For a basement that is not connected to the rest of house HVAC, I would get a separated de-humidifier, as others have said.

If you want to duct the basement and hook it up to the rest of house forced air HVAC that can be done too.  We have that in our house.  The AC and furnace are over-sized and we use the ducts to help make the system moderately more efficient (for example to direct the AC to the top floor in the summer).  But it might be simpler for you to go mini split - we got our house in the current configuration and didn’t want to start ripping out walls.

Finally cold basement floor is an issue but address it by getting a thick, insulated pad under the carpet.  We did that in our basement and you can walk around down there in the middle of January bare foot and you cannot feel any cold.

HTH.

Related-  what about protection from basement flooding?? In a previous house (where I had an HO scale layout) we got 4 feet of water when the big grid failure in August of 2003 and the following electrical power outage.   Everything UNDER the layout was ruined.                   

Now I have a city water-powered backup system to my sump pump.  This system has a separate water level sensor (above the electric sump pump float) so that, in the event of an electrical outage or sump pump failure, the city water-powered system through a siphon device pumps 3 gallons out of the sump every 5 gallons of water.  So for the water to flood the basement,  we would have to have an electrical outage, and/or a sump pump failure, in addition to no city water supply.

Plus I replace the sump pump about every 5 years.

Mini-splits are great for rooms that cannot be connected to a central system. I agree that a good dehumidifier is a must regardless of the other systems in place.

Another option is a portable AC unit. I bought one several years ago for our basement and it does the job when necessary. One change I made was to use insulated flex-duct for the condenser exhaust instead of the plastic flex pipe that came with the unit. The condenser discharge air is about 90 deg from the unit, no sense in putting that heat right back in the room.

Bob

Great comments, guys! Thanks for the advice.

Chris

LVHR

@RSJB18 posted:

Another option is a portable AC unit. I bought one several years ago for our basement and it does the job when necessary. One change I made was to use insulated flex-duct for the condenser exhaust instead of the plastic flex pipe that came with the unit. The condenser discharge air is about 90 deg from the unit, no sense in putting that heat right back in the room.

Yep, clearly exhausting the hot air out of the conditioned space is mandatory, otherwise it's really just a dehumidifier and is heating the space!

How well does a mini-split work for heating? Is it also a heat pump? Or do you need some alternative heat source? I'm in PA, and the outside temperature is 3F this morning!

Chris

LVHR

I’m in PA also and awoke this morning to a balmy 2 degrees. We have mini splits throughout the house; and train room. Consistent comfortable temperature throughout. Love them all year long.

Jay

@lehighline posted:

How well does a mini-split work for heating? Is it also a heat pump? Or do you need some alternative heat source? I'm in PA, and the outside temperature is 3F this morning!

Chris

LVHR

Most Mini-Splits are heat pumps in fact you’d probably find it more difficult to find one that was cooling only but they are out there. Best thing I can recommend when having someone install it is make sure to go with the “Hyper heat” model as that is more likely to have less issues trying to hear in cold weather. FYI Hyper heat is brand specific but every brand has their own version.

Two things as far as operation goes.

1. Mini Splits will always try to heat even if they know there is something diminishing their performance. While this may not apply in a basement if there is a “ bonus” room then don’t let it get below 60F or it will be very difficult to come back from that once ODA is below 32F.

2. Mini-Splits do nothing for IAQ (Indoor Air Quality). Their filters are a joke but still catch more than you’d expect issue is what gets by the filter collects on the blower wheel. May take 5 year for a noticeable issue but with the dirty wheel it decreases the air volume enough that it can severely affect the performance. So if there seems to be a high amount of dust and stuff in the air a separate air purifier would be recommended. Or run your whole house HVAC in “Fan On”

@lehighline posted:

How well does a mini-split work for heating? Is it also a heat pump? Or do you need some alternative heat source? I'm in PA, and the outside temperature is 3F this morning!

Chris

LVHR

Make sure you get "cold climate" rated systems. They are designed to work down to lower air temps.

Ducted heat pump systems are available with electric heating sections for "emergency heat" when the HP alone can't keep up with the load.

General note too- make sure you keep the snow off of the condenser section or they won't work because the airflow gets blocked.

Bob

We built so the basement was finished with normal HVAC.  We built under our attached garage, it was the cheapest per SQ option, since out lot is only 50x150, old suburb of Chicago.  Did add a dehumidifier that drains into a sump pump pit since even with the AC running, the humidity was too high.  Set it at 45 and it runs a few months a year, probably won’t kick back in until July or so.

@RSJB18 posted:

Make sure you get "cold climate" rated systems. They are designed to work down to lower air temps.

Ducted heat pump systems are available with electric heating sections for "emergency heat" when the HP alone can't keep up with the load.

General note too- make sure you keep the snow off of the condenser section or they won't work because the airflow gets blocked.

Bob

Bob makes an excellent point and ours are mounted a respectable distance from the ground. In addition to snow I make sure that leaves don’t get sucked onto the back of the outside units.
Jay

@lehighline

You’ve received some nice pointers from those who’ve had to install various kinds of Heating and Ventilation/Air Conditioning systems for their train rooms.

But again, since you are only in the “giving serious consideration to moving” stage and haven’t done it yet, consider a finished basement that’s already HVACed. Then you wouldn’t have to worry about any of the above. 😉

@lehighline posted:

How well does a mini-split work for heating? Is it also a heat pump? Or do you need some alternative heat source? I'm in PA, and the outside temperature is 3F this morning!

It was 8F here this morning, and my basement mini-split was blowing nice warm air.  I don't see a spec for the lowest operating temperature, but since it rarely gets much below 8F where I am, it works for me.

A few years back, in central PA, the air temperature was -4 when I got up. Not a problem.

Excellent info! Thank you!

Chris

LVHR