Greenhouses, Sheds and Sun Rooms - Sunroom Choices

I have been doing a lot of research and have had a couple companies come out to give us estimates for putting a sunroom onto our house - none of them cheap and none of them perfect... After finding this forum last night and reading every post that contained "sunrooms" in it, I still have quite a few questions...

First - the basics. We live in central Massachusetts. The sunroom addition would go where we currently have a patio. It is off of the kitchen and is surrounded by 3 brick walls - 2 that are 2 story house walls and one that is a one story garage wall. I would prefer a glass roof because a regular roof would pretty much cut out all of my natural light coming into the kitchen.

Question 1 - What is the prefered subfloor for a sunroom? One company has quoted a full 4 foot poured footing and poured slab. Another insists that sonotubes and 2X10 with insulation and plywood are the way to go because it would be a "warmer" floor...

Question 2 - Is there any internet resource that compares sunroom companies and products - apples to apples? For example, I find 4 Seasons relying on the R value of their glass, but I understand that U value is what you need to look at due to the heat transmission of the different frame types. How do you compare these products without standardization? I did find the NFRC website, but there are no numbers there, just companies listed and the brochures I have don't list the numbers...

Question 3 - If you want to make this a full 4 seasons room in this climate, what is the best heating to go with? We have radiators with a couple of radiant floor zones. Would that be prefered in the sunroom? Would hot water baseboards be sufficient? I read a post that talked of the electric mats you put under the tile. Would this be enough to heat the room? Would it be best to do baseboards with the electric as a backup to add on when it gets really cold?

I'm happy to share details of my investigation of different companies and the different quotes we've gotten, but figured it best to start here... I'd be interested in any help any of you can give me!!

Thanks!

The FIRST thing you need to decide is if this room is going to be a PATIO ROOM (non-conditioned space), or it it is going to be an ADDITION to the house (conditioned space). THAT will determine how you go about building it.

Conditioned space is going to be a lot more expensive than non-conditioned space. It has to be energy efficient. (That opens a can of worms.) Your HVAC has to be sized to handle the addition. (You MAY have to increase the size of your HVAC unit.) And, at least in CA, it is going to be taxed differently. (Patio rooms add virtually nothing to your proerty taxes here, but adding a conditioned room (living space) over 200 sq. ft. DOES prove to get costly.

I think our answer is "conditioned space" because we would like to make it into something we could use year round. However, we do not plan on taking out any of the doors or windows that connect to the space, so we could keep it closed off when it is too hot or cold out there.

We have no A/C so we are only talking about heat. If we treat it as an "unconditioned" space, is there a problem with putting some sort of heating out there? Does that automatically turn it into an addition instead of an enclosed patio? I guess I need to go talk to our building inspector AND tax assessor and see what their read on all of this is.

Meanwhile, I need to start making some basic decisions between companies and products. I AM looking for as efficient as possible. I want a decent space that doesn't get too hot or cold and doesn't have condensation issues. So far we have had 4 Seasons Sunrooms, a local contractor that deals in C-Thru and K2Conservatories, and Brady-Built of New England come out to give us estimates. 4 seasons is the low bid at this point, but it is an aluminum room and the one thread on here that I read about condensation has scared me away from that - I don't think they have taken care of the thermal break issues in their standard aluminum room. The C-Thru/K2 quote was next in line (about $3K higher) and is a vinyl room with what I think a more energy efficient frame and is a CUSTOM build so it would fit the space perfectly, unlike the 4 seasons which because of our C shaped space would have to have "fillers" in the roof and front frame. The Brady-Built is an aluminum/steel frame with lots of wood beams on the inside and is a one piece structure that would be built as a unit in the factory and hoisted over the house and put in place on either a slab or insulated wood foundation and is about 35% higher than the other 2 quotes. We also have the local Lindal contractor coming out to give us a quote, and my guess is that their price will be even higher...

How do I find out the true differences in efficiency between these rooms? If it is U value of the total product, where can I find that information? I really want to be able to compare apples to apples on efficiency and I'm having a REALLY hard time getting the data to do that. I have spent hours on the computer google searching and no matter what I find it ships me to some dealer's website and all I'm finding is hype or values that aren't comparable with the other dealers. From what I understand, R values of the windows don't tell you at all how the room is really going to perform. If the frame conducts the cold in, it doesn't matter how well the glass performs. It is THE UNIT as a whole that has to be evaluated. Where can I find this information?

Any and all help is appreciated!

stillriverpottr,

When you say "I guess I need to go talk to our building inspector AND tax assessor and see what their read on all of this is" -- truer words have never been spoken!!!

What the building depts. require vary from one to the next. What I can build in Shasta County is NEVER going to fly in the City of Redding. And the other 2 counties and 5 cities I deal with are all somewhere in between. So, as a contractor, I have to know not only what I'm doing, but WHERE I'm doing it!!

And how the Assessor's Office deals with it -- I really don't have a clue. I know that my patio cover and non-conditioned sunroom added virtually nothing to my property tax bill when I added them 10 years ago. But adding 170 sq. ft. of bathroom and closet added about $100 to the tax bill.

I've installed several different brands of patio enclosures, some 3 season, some 4 season. I've also installed several "Sunshine Room" brand curved glass solariums, and a huge aluminum framed all glass conservatory. As I can recall, the conservatory had a footing, with poured stem walls that brought the walls about 2ft above grade, where the glass walls began. The floor was poured cement, with HVAC ductwork all below the slab. Ceiling fans were installed in the peak of the room to circulate air.

One solarium had electric baseboard heat, the other had shared heat from the HVAC ducts coming out from the house. Another 3 season room (aluminum frame, 2" foam panels, sliding glass windows) had an electric heater unit installed, and the family that owns it has been very happy with it and use it practically year round despite the cold winter temperatures here in Nebraska. Another 3 season room I did had no supplimentary heat at all, and to control the heat, we added an additional 4' roof panel onto the south side to create an exterior porch area, which provides enough overhang to prevent sunlight from coming directly in through the windows in the summertime.

The curved glass solariums all had fabric venitian shades with heat reflective surfaces, which can be drawn up or down, depending on your needs. Choosing the right type of glass will be important for you, because you will likely want the maximum heat gain in the wintertime, while reflecting incoming heat in the summertime. I believe that would mean you'd want a twin coat low e. (low-E2) But don't quote me on that. I'm an installer, not a salesman!

Ideally, I think you want forced air, since moving air will help to warm the glass and circulate the air so that you get more of an even temperature throughout the room. Electric baseboard heat often doesn't provide the circulation unless they're coupled with some ceiling fans to move the air.

Poured walls and footing are more substantial, and you won't have a problem with animals / weeds underneath like you would with sonotubes and piers, even though structurally, putting a room on piers will work, provided its engineered correctly. Poured walls and pads can be insulated to isolate them from the freezing temperatures outside.

As far as their definition of "conditioned space" is concerned, you'd be smart to find out. If it saves you thousands in taxes, to keep it "unconditioned" you might be better off putting in several plug-in space heaters, which might work just fine.

Thank you for your replies! I have been meaning to get back to this project and now am heading back into it with MORE information and probably more confusion as well...

I've made 6-7 trips to visit the assessor and building inspector over the past 6 months. What it comes down to here is if you COULD heat the space (whether or not you do), it is considered an addition and is treated as additional floor space. The amount the taxes go up is directly related to how much you spend, so we are looking at anywhere between a $500 (to $1000!) raise in taxes per year to add on a sun room. So, is it worth it? Truth is, I don't know... I ran into a couple little snags with building codes, but those are all well/septic related...

I feel like I'm a fairly intelligent individual, but I'm not finding information that is allowing me to compare apples to apples between these different contractors and their products. The frame is just as important as the glass for insulation, but there is no "overall" value that you can compare. The prices are all over the place and one bashes the other when you sit to talk to them, and no one clearly comes out on top. I just don't feel comfortable that I'm getting a straight opinion from any of them, so I have done nothing. Meanwhile, 2 have dropped their price and I've ruled out Brady on cost alone ($80K+ for our installation!).

Is there any source out there for comparing sunroom products against each other for efficiency? I want a quality product and feel like I'm willing to pay a reasonable amount for it, so why is it so difficult to measure these products against one another?

Still pondering the sunroom question...