Turning a Sunroom into an All-Season Room with a Ductless Mini-Split

Mike Cappuccio of N.E.T.R., Inc., Mike discusses how many sun rooms are only used in 2 seasons, Spring and Fall, and how standard options for heating and cooling these rooms fall flat. Enter the Ductless Mini-Split, a quiet and economical way of turning your sun room into useable space, year round.

John: Hi, I’m John Maher. I’m here today with Mike Cappuccio, owner of N.E.T.R., Inc., a heating and cooling company in Massachusetts with a focus on Mitsubishi Ductless heating and cooling products. Today we’re talking about turning a sunroom or three season room into an all season room with a ductless mini-split. Welcome Mike.

Mike: Good morning John. How are you?

What Is A Ductless Mini-Split?

John: Good, thanks. What is a ductless mini-split? And will it really keep my sunroom warm in the winter and cool in the summer?

Mike: Great question. A ductless mini-split is basically composed of two things, John. It’s an indoor unit and an outdoor unit. I don’t know if you’ve ever seen one, but it’s a white heat box that mounts on the inside of the sunroom, and then outside there’s what’s called the condensing unit. Really, we have two pieces; an indoor unit and an outdoor unit. They’re connected with two pipes, a wire, and a drain that goes to the outdoor unit. It’s really, what it is, is we make a three-inch hole from the indoor unit to the outdoor unit and run piping down out to it.

What If My Sunroom is Mostly Windows?

John: How do I put a heat pump in my sunroom when it’s mostly made of windows?

Mike: It’s mostly made of windows. A lot of times, John, when we go in and we look at a sunroom, first off we look at a sunroom/three season room and nine times out of ten it’s not a three season room, it’s a two season room, because people find out that we can come out here in the spring, we can spend a little time out here when it’s cool, when we have the 60 to 70 degree days. But then in the summertime, it gets extremely hot, and we don’t spend any time out here because it’s all windows and it becomes a solarium at that point. Then in the winter time, it’s too cold. It’s really not a three season room, it’s a two season room.

John: Spring and Fall.

Mike: It is a sunroom, but it also becomes a solarium as well. But we’ve taken many of those rooms and turned those into actual living space.

John: That you use all four seasons?

Mike: We use it all four seasons. When we come out we look at the sunroom. If it does have windows, it’s all windows, well usually that is off the back of the house, or the side of the house, and there is an interior wall that we can put a unit on. We look at that wall and say, “okay, can we open up that wall? Can our carpenter open that? Can we put piping inside of that wall and bring it down below the sunroom and bring it out to an indoor unit? Or does that wall maybe back up to the attic of the home where we could get piping and drains into the attic and then bring them out the soffit of the home to the outside?” There’s a lot of different ways.

The other thing is, too, a lot of times the windows are up high and we have a three-foot space across the bottom. We also have, from Mitsubishi electric cooling and heating products, we have a floor mount unit. That, actually, is about two feet tall, two feet wide, comes about eight inches off the wall, and we can mount the floor mount unit down low on the wall. We can look at that interior wall, or we could look at those exterior walls as well depending on the situation.

John: So there are options that you have there?

Mike: There are a lot of options.

John: When you think, “Oh, my room is all windows,” generally it’s not really floor to ceiling windows. Like you said, there’s space at the bottom or there’s some in the corners where maybe there are no windows, and you have some options to mount it there or whatever.

Mike: Yes. We see a lot of times the sunroom builders will go out — or the three season/two season room — they’ll go out and they’ll build that room. You might spend $50,000 or $60,000 or $70,000 building this room. I’ve seen some of them even higher than that. Then, usually what happens is on the bottom wall of that, they put what’s called the PTAC unit in there and it’s almost like a hotel room unit that goes into the wall and they put it into the bottom.

It’s just the most inefficient way to heat and cool that room, because you’re in a heat pump situation now, where you have an old heat pump technology, it’s not a hyper-heating technology product. It has backup electric heat in there. It’s very, very loud. The compressor is actually inside the unit. About a year or two later we go out to the homes and we see them sagging, they’re just so heavy. The backs of them are sagging, the wall panels are pulling out. We’ve removed a lot of those and put in the Mitsubishi floor mount unit in place of that.

John: Yeah, and those sunrooms; the whole point of having a room like that is, kind of, a place to escape to, a place to relax in. With noisy equipment like that in there, that’s not going to be a place where you’re going to want to go.

Mike: It’s not the place where they end up going. A lot of times, too, we see people that build this room and the builder might come out and go, “Okay, well, you know, we can just take a duct off of the additional system that’s in the house. Well, we’ll just take a piece of ductwork, and we’ll run it up through the attic. And we’ll poke it out through the ceiling in the sunroom. And we’ll throw one heating vent out there or a cooling vent out there.” Now, you have one thermostat in the house. You have to turn the thermostat up or down, up in the winter time to heat the space. Nine times out of 10 you don’t have any return duct in there.

It just is the most inefficient way to do that, to heat and cool one room in the home.

John: Especially when, like you said, that one room, that sunroom, is going to get really hot in the summer and it’s going to get colder in the winter, which is different than the rest of your house. How do you balance that with one system?

Mike: You can’t balance it; you’re going to end up turning the thermostat down inside the house to 65 degrees. The house is going to be freezing. The sunroom is all windows. A lot of people don’t understand, with windows comes a heat load and a cooling load. When you look at that space, that’s not your typical — let’s say that’s a 20′ x 20′ sunroom, and it’s all glass. That’s not like a 20′ x 20′ room in your home that might have four or five windows in it. You have a lot of glass out there on a sunny day that’s going to get very, very hot. On a cold day it’s going to get very, very cold.

That’s where we have to look at the sizing of that. We have to really run what’s called a Manual J load calculation on that room, and figure out what size unit we need in that home. A lot of times a homeowner will go out and they’ll buy an air conditioning unit for that space and they go to the big box store and they tell the guy at the counter, “Hey, I have a 20′ x 20′ room.” They say, “Okay, that’s 400 sq ft. You need 12,000 BTUs to put in that space.” Well, that’s not really what you need in that space. With the glass and things like that in that space, you need more heating and you need more cooling.

That’s why we come out, look at that room, determine your exact needs of that. Most times we see that’s anywhere from 24,000 to 36,000 sometimes because of the actual heating and cooling loads that you’re going to need in that space.

Is Remodeling Required for a Ductless Mini-Split Installation?

John: Will you generally need to do any major remodeling to install the ductless mini-split?

Mike: If we’re going to go on the interior wall, there is no major, major work that’s going to done. We would have our carpenter come out there with us, he’d cut a little chase in that wall, if that’s drywall. We would patch the drywall back up. Resand it. Refinish it. Repaint it. Do what we would have to do to that. We have a carpenter on staff at our company that would do that with us. Sometimes the homeowner has a carpenter.

If it’s going to go on the lower walls like we were discussing and it’s going to be a floor mount unit, no, that’s just “poke a little hole outside” and run that to there. Most times we’re out of there in one day. If we’re going to do the interior work, probably two days. But it’s not major construction, no.

Noise Levels of Ductless Mini-Splits

John: Talk a little bit more about the noise level of these ductless mini-split versus traditional window air conditioners.

Mike: Oh god, that’s like night and day. The window unit actually has a compressor inside of it. That’s what is the bulk of the noise with the system, the rattling, and the on and off, on and off. You hear the compressor turning on, turning off.

With the ductless system from Mitsubishi electric, that is just an indoor unit. The only thing that’s inside the space is really just a little fan. The fan has multiple speeds on it. Sometimes upwards to eight different speeds you can run that at. That fan can ramp up and ramp down with temperature. As the room gets cooler or warmer, whether you’re set on heat or cool, the fan speed slows down. It’s about 28 to 30 decibels on low. That’s pretty much a human whisper, what you’re going to hear inside that space. Very, very quiet when you’re going to hear the fan running inside of there.

And the outdoor unit, when that’s on, that’s an inverter driven unit, and that speeds up and slows down with temperatures. When you’re outside and you’re looking at that outdoor unit, sometimes you’re going to see the fan running real fast. That would be if the temperature is trying to pull down to temperature in the cooling mode.

Say it’s 90 in the room and you trying to get 70. It says, “Okay, 20-degree temperature difference.” It needs to pull down real fast. So the fan outside will run real fast and the compressor will run real fast. As the temperature cools down in the room, the compressor slows down, the outdoor fan slows down, the fan inside the room slows down, and just goes into a nice “cruise-control” mode like your car out on a freeway. Just running nice and smooth, and nice and efficient, and getting highway gas mileage.

It’s pretty much what you’re doing with your electricity too. You’re getting a nice rate of electricity, nice low energy bills to heat and cool that space. If you’re not in that sunroom, you turn it off, or you can turn the temperature down, or turn it up, whatever you want to do in there. It becomes its own zone.

A lot of people make mistakes with that when they go out, and like I said, they try to add ductwork in there, they try to put a window unit in there. They look at all these other options and then they figure out, well there was another option. It was a little more costly to do it, but now they’re doing it when they’ve already done the first option. In reality, did they save money? No, because now they’re having to do it all over again. See, that happens a lot.

John: All right, that’s really great information, Mike. Thanks again.

Mike: Thanks, John.

John:  For more information visit N.E.T.R., Inc. website at www.netrinc.com or call 781-933-NETR. That’s 781-933-6387.

0 thoughts on “Turning a Sunroom into an All-Season Room with a Ductless Mini-Split

  • Fredric Buchanan says:

    I have 13×13 size. Sunroom that is all glass. I would like to add a mini-split but can’t find
    the proper location. What can I do to provide the cooling and heating for this room?

    • Hello Robert, if you’re in the Easter Massachusetts to Southern New Hampshire area, you can fill out the form on our website to request a free consultation. If you’re not in our service area, we recommend reaching out to your local Mitsubishi Diamond Elite dealer.

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