GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

HVAC Retrofit for 1918 Colonial Revival in CT

Pagan11460 | Posted in Green Products and Materials on

My husband and I own a 1918 Colonial Revival in CT… where summers are hot and humid and winters are cold. We bought the house 4 years ago. But we’re not spring chickens… we’re in our 50s so we won’t see as much return on investments as say… a younger couple might. (We have no children but my husband’s elderly uncle might stay with us in Feb. 2016 so we need efficient heat for him.) We also don’t have a big budget – plus our house is in a neighborhood where the houses are losing value, so we don’t want to spend a tremendous amount on renovations. But we do love the house and can’t afford to live elsewhere so we do want to renovate – so long as the expense makes sense. With that being said… I despise our radiators! And I want them gone. We have a gas boiler in our basement – 6 years old… but we will need a new water heater soon… was thinking of tankless. We only have one thermostat and it’s in our dining room. I’ve made an office out of our sun porch. It has lots of windows. It’s freezing cold in there in the winter and boiling hot in the summer. I use a space heater and still I’m cold. We heat the entire house all day, every day during the cold months due to the one heating zone – while I only work in one small office/sun porch and my husband is at work all day. By the time we go to bed at night, the upstairs is so hot that we need to open windows and sleep with a fan. But I use a blanket while we watch TV downstairs.

I’m trying to figure out how to change all of this… I want efficient heat that can be zoned – per room if possible and if affordable – if not, then at least zoned per floor. (2 floors for now, maybe a finished basement someday.) I’d also like efficient air conditioning of some kind. And – yeah – I’m asking for the impossible – I would love to have smart thermostats so that we can control the heat and a/c online. I *love* the Honeywell Lyric because it can work with Apple HomeKit and I can control it with my voice via Siri with my Apple TV or my iPhone or – someday – my watch! But I don’t think it’s compatible with at least one of the options I’m looking into… any of the ductless mini splits.

I’ve researched lots… looked at Ray Magic out of Italy and California… radiant heat and A/C… supposedly easy enough for a DIY but I’ve been told it’s better for dryer climates than CT’s humid summers… plus it’s expensive to ship. I looked at Warmboard but I somehow thought that it would run both radiant hot water for heat and radiant cool water for A/C – I learned today that I was wrong. It is only radiant heat. I called several HVAC guys in the fall of 2011 for their suggestions… they suggested forced hot air but their prices for our 2,000 sq ft home were $28,000 to $34,000… probably higher now and I don’t think that forced hot air is efficient – plus I have to give up closet and attic storage to make room for ducts. I like the idea of ductless mini splits but only if I can have ceiling units. Can’t have those ugly things on my walls. But I want to get rid of our radiators entirely and – if we go with a ductless mini split system, I *think* that we have to have a heat fallback in case it gets really cold… I think Mitsubishi can allow for -13F temps but I think that’s only with the ugly wall units not the ceiling units. Plus if we remove the radiators, what would we do about alternative heat in -13F weather? I was thinking that we could install a gas insert in our downstairs fireplace with a blower and add a vented gas fireplace with blower to our master bedroom in our upstairs for days that get really cold… and we’d have to leave doors open for those days. Would that work? Last option… Energy Saving Products makes a small duct hi velocity system similar to Unico and Spacepak, but supposedly better. I read some comments by Martin Holladay about Unico that made me question the hi velocity idea. But I saw others argue about the good points of small duct hi velocity systems. I wish I knew who to believe… especially because sdhv systems supposedly purify, ventilate and dehumidify as well. But I have no idea what they cost. Even if it was $28,000 to $32,000, we might consider that if they really do work and if they also purify, ventilate and dehumidify. I just have no idea where we’d get that kind of $$.

I should add that we have no insulation at all in this house but we plan to insulate the attic and around the perimeter of the basement with some type of insulation… and – if recommended – in the walls with cellulose. We also have double pane windows. It costs us about $2,000 for gas to heat this house each winter, not including electric for my space heater.

We have a big living room, a small dining room and a kitchen (with no exhaust fan) plus office/sun porch, bathroom (also with no exhaust fan) and a foyer on the first floor. Our staircase is against the exterior wall and then we have a very large master bedroom with a walk-in closet, a large guest room and a small guest room plus a bathroom (with no exhaust fan) on the 2nd floor. We have a stairwell off of our walk-in closet that leads to an unfinished and very hot or very cold attic. We have two window vents in the attic that we open and close as needed. We know that we need proper ventilation and insulation in the attic because we get ice damns in the front of our house every winter.

So… my questions are… what would be a good HVAC retrofit? Do we need another source of heat if we install a ductless mini split system? Would gas fireplaces be an option for an alternative heat source? I hear that DMS is not expensive, then I hear that it’s very expensive to install. I have no idea who to believe. Can anyone give me a rough idea of installation costs. Should we insulate our exterior walls? If we insulate really well, could we forgo a/c or is CT too humid for us to not have any a/c? Is there anything that we can DIY in order to afford any of these heating/cooling ideas?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Pagan11460 | | #1

    P.S. Wow. I didn't mean to write so much. But I've been searching online all day today and I can't find any answers. I keep finding arguments over which is better - DMS or SDHV... and other arguments over whether SDHV even works.

    If anyone can manage their way through all of this, I thank you and I'd love to hear your thoughts.

  2. STEPHEN SHEEHY | | #2

    Margaret-It may be helpful to think of your situation as a cold, drafty house problem, not an HVAC problem. You need to tighten up the building envelope first. Your existing, six year old boiler may be adequate once you do that. Does it use natural gas or propane. Right now, natural gas is pretty cheap and it may not be cost effective to switch to mini-splits.

    Usually, the most bang for the buck is air-sealing. Start with air-sealing the attic, then insulate it. Ice dams are caused by warm air leaking through the roof. Insulating the attic floor should help.

    Insulating the rest of the house would help a lot. Do you have storm windows? Replacing the double-hungs would be expensive and probably not the best use of your money, but storms could help with the drafts.

    Once you air-seal and insulate, see where you are. You may find that you are comfortable enough without a new, expensive HVAC system.

    As for mini-splits. I'm in Maine, where it gets to -20 on occasion. I haven't been through a winter yet, but I'm pretty confident that I'll be OK, but that's because I have a tight house and the mini-splits will still produce some heat even at extreme cold times.The esthetics are a different issue. Ugliness is subjective. I've been living with the wall units since June and hardly even notice them.

    There are more attractive radiators on the market than the old, big cast iron ones.

  3. GBA Editor
    Martin Holladay | | #3

    Stephen gave you good advice. You have a leaky, uninsulated house. Focus first on fixing your thermal envelope -- that will make you more comfortable and will lower your energy bills.

    You need to hire a weatherization crew or a home performance contractor familiar with blower-door-directed air sealing. Most of the air sealing work will occur in your basement and your attic. If you want to do the work yourself, read these two articles:

    Air Sealing an Attic

    Air Sealing a Basement

    Once you have completed as much air sealing work as you can possibly perform, it certainly wouldn't hurt to beef up your home's insulation.

    You wrote, "I despise my radiators," but you don't tell us why. If you really just hate the radiators (rather than hating hydronic heat for some reason), you can keep your boiler and replace your radiators with hydronic baseboard units.

  4. Dana1 | | #4

    What Stephen said- the most cost effective thing you can do for comfort is to air-seal and retrofit insulation. There are significant subsidies in CT for that sort of work. The most efficient mechanical systems in the world won't make you comfortable in a drafty barely insulated house.

    Replacing century old wood sash double hungs is rarely cost effective, but it's cost effective to tighten them up with new/better weatherstripping & pulley seals. If it has leaky old storm windows it's cost-effective to replace them with tight low-E exterior storm windows. (Harvey has the tightest storms in the biz, and they have a hard-coat low-E glazing options. The Larson low-E storms sold through box stores are decent enough if you upgrade to the silver or gold series. The low prized bronze series is too leaky.)

    The the new-improved lower heat load you can probably build out radiator covers if you can't stand looking at them and still have enough radiator output to heat the place.

    But there's no way to recommend outright replacements until the heating & cooling loads are known. Start by having an energy audit (usually done through the electric or gas utilities), and TELL them that you're interested in doing some serious air sealing and insulation upgrades, not just a box of CFL bulbs and a smart thermostat. Then hire an energy nerd to run an aggressive Manual-J calc on the "after" picture, using only the 99% outside design temp and 68F for an interior design temp (the code-minimum) for heating, and the 1% outside design temp and 76F for the interior design temp for cooling, so as not to oversize the systems. You can keep thermostat settings whatever you want, and it WILL keep up, since the step sizes in equipment are bigger than that. What you want to avoid is overestimating the loads, then taking on even bigger equipment, and end up less comfortable & less efficient due to oversizing.

  5. Pagan11460 | | #5

    Wow! I'm so impressed with all of you and with your responses. Thank your so much for taking the time to respond. I worried that I wrote so much and asked so many questions that no one would read this... so much so that I failed to say why I hate the radiators! I hate them for several reasons --- one reason: only having the one zone and heating the whole house while I'm using only one room in the house and my husband is at work. But mostly... I hate them because they're in the way.

    We have a huge living room and a small dining room and I want to be able to expand my dining room table. So... I am making my living room into a great room by putting my dining room table in the left-hand side of the room and then making a smaller living room space out of the rest of the room. I want to add a sectional into the right hand corner of the room. Can't do it. Why? There's a huge radiator under the three windows in the center of the room. I have no place for even a couch, never mind a sectional. (We have arched openings from the foyer into the living room and from the living room into the current dining room. The arched doorway leading into the living room is so big that I don't have room to place a couch against that wall. But if I get rid of the radiator, I could fit a sectional in that corner nicely.)

    When I eventually knock down the wall in our current dining room to make it into a great room (kitchen/den/TV room leaving the formal dining room and living room all in one room in the front of the house), I want to add a corner banquet to the left wall. We can use it as a couch and - if we have more than 10 people over for dinner, I can place a table in front of the banquet in the great room/den and that will expand my dining area into this room. I can't do it cuz there's a radiator in the way.

    We have a small bathroom off of our kitchen. It was once a pantry but the previous owners added a bathroom with a stand-up shower. It's hideous and in dire need of updating. But until that day comes... with the door open, from our kitchen, what do we see? A toilet! That's awful! I want to close up the door to the bathroom from our kitchen and open up a doorway into the bathroom from my office/sunroom. It will stop us from seeing a toilet in the kitchen and it will give me more much-needed counter space in the kitchen. But I can't do it because there's a radiator in the way. My husband has bad knees. I need to add a stair lift. I can't do it because there's a radiator in the way. We need to take out our upstairs tub and make a European shower so that my husband doesn't need to step over the tub with his bad knees. But there's a radiator in that bathroom - so there are holes in the floor for the pipes. Even if I could plug up those holes and get that European shower, I still have radiators in the way in every room of this house. I'd like some other way to heat and air condition all of these rooms… some other way that's not in the way and that's not so visible.

    Plus, we don't have air conditioning. So... even if we kept the radiators, which I *really* don't want to do, I would still need to add a/c. So my thought was to kill two birds with one stone... swap out the radiators for ductless mini splits or a small duct hi velocity system. I thought that replacing the radiators with one product that can heat and cool would be less expensive than swapping out the radiators for slimmer Runtals and still having that same radiator-in-the-way problem only now they're slimmer and then adding A/C some other way.

    @Stephen Sheehy… excellent advice… re: "[i]t may be helpful to think of your situation as a cold, drafty house problem, not an HVAC problem." I know that I need to tighten up the house first but your advice air sealing is just what I needed to hear. Re: our boiler… I don't think that the boiler is inadequate. It works fine. I was just mentioning it so that, should anyone advise me on other hvac solutions, they'd know that we have a gas boiler… but I failed to mention that it's a natural gas boiler. Even though natural gas is affordable, if I could find a way to not burn fossil fuel, I'd like to do that. I have heard of the savings people are getting with ductless mini splits so I thought that would be a good solution even if it means getting rid of the gas boiler. You asked if we have storm windows. But I had said above that we have double pane windows. Do we need storm windows as well? The previous owner changed the windows over to double pane windows about 6 or 7 years ago. I don't know what brand name they are… probably not the best name brand so I don't know how efficient they are but they are double pane.

    @Martin Halladay… a thousand thanks for the links on how to air seal. Now that I know more about what that entails, I think I need a pro. While I'm probably capable of the handiness needed to do all that, I think I'd rather have a pro's expertise. If I did something incorrectly that caused mold or any other issues (like death from poisoning!), I'd be upset later on that I attempted to DIY, if I lived long enough to be upset. It could be penny-wise and pound foolish to DIY.

    But meantime, even before I do call in a pro for air sealing, I think I need to address some electrical issues. We don't have enough outlets in this house and --- some of them are still two-prong… in the baseboards… not in the walls - so I believe that they're not grounded and I believe that some of them are wired from some old knob and tube in the attic. I need to address that.

    I think my first order of business is to draw up some plans (not professionally with an architect… I can do this part myself using Adobe Illustrator just so that I can show an electrician the plans that I have layout wise and where I need additional outlets and lighting.) Then, I need to get an electrician in here to do a bit of the work now… some of it, he won't be able to do until after we knock down the wall in the kitchen. But at least I'll have most of the electrical done while it can still be accessed --- before adding insulation and caulking, etc. Am I correct to think that way?

    @D Dorsett, re: there are significant subsidies in CT for that sort of work. I found the DSIRE website last night. I plan to look into it further. We have double pane windows. I hope that we don't need to replace them… but if we do, the advice on the replacements is very helpful and all the other info re: energy audits and testing is fabulous. Thank you so very much.

    So… now that you all know that we want to get rid of the radiators cuz I want to place furniture where I want and I want to add a stair lift and I want a European shower for my husband to walk into the shower - or roll in when the time comes for him to use a wheelchair --- after we tighten up the house --- do you think that ductless mini splits would be the smart choice? If so, almost everything that I read says that ductless mini splits are "supplemental" and that we'd still need an alternative for cold days. D Dorsett said that he thinks his tight house and mini splits will be enough. Steve and Martin, do you agree? A friend of ours (HVAC guy) says that we will need a supplemental heat source but he wants us to keep the radiators so maybe he's biased. We already want to add a gas insert into our living room fireplace and we already want a vented gas fireplace in our bedroom. So… I'd like to know if these two gas fireplaces could be considered supplemental heat if they had a blower - if we experience a bad cold spell. (Who knows what the weather will do in the future? Ten years from now, we could have really cold weather more often than what we're experiencing now.) I need to keep resell value in mind. Having supplemental heat would probably help. Meantime, are they expensive to install? I see what others have paid online and it runs the gamut from affordable to outrageously expensive. I'd like to hear what you know about price with all of your collective experience… do you have an idea if they're pricey or reasonable or what? Do any of you know if they make ceiling models that can heat our home if it gets terribly cold -- or if not, can I still get ceiling units and then use the fireplaces with blowers as a supplemental heat source? (@Steve, even though you don't notice them on your walls, there's no way that I am adding those wall units to the walls of my 1918 Colonial Revival. I don't like the look of them for our period house.)

    I love the idea of small duct hi velocity. Like I said in my first post above, some people love them. Others don't think highly of them. If they work and they don't cost $50,000 to install, they would be my first choice for aesthetic reasons… even if it meant burning fossil fuel -- and even if we couldn't do zoned heating. I think that we can use the Honeywell Lyric with them and I'd like to use that thermostat. So I was hoping to find out if you had any idea how much it would cost to install them in a small Colonial Revival (after the house has been tightened up - per your fabulous advice).

  6. Expert Member
    Dana Dorsett | | #6

    If the double-panes are clear-glass (no low-E coatings) it's still worth considering low-E storms, but it's less of a priority.

    If you have a heating history, we can use the heating fuel use and the boilers nameplate efficiency (DOE-output BTU divided by the input BTU) as a measuring instrument to put a firm upper bound on the where-is-as-is heat load of the house in it's current condition, which is at least a start. We would need some early or late winter gas bills with the exact FUEL (not dollar) amounts and the exact meter reading dates, and a ZIP code (for both outside design temperature and weather data). Don't include billing periods when there was extensive use of electric space heaters.

    If the $2000/year fuel cost was all buck-a-therm gas you're probably looking at a heat load of about 60,000 BTU/hr (give or take 10K), which would be a VERY leaky and uninsulated 2000' home.

    I'm a big fan of ductless technology when they're sized correctly, but without a good handle on your actual load numbers it's hard to say if there are reasonable ductless solutions for you. To get it right you would need to have careful room-by-room heat load calculations already in hand to figure out the head/cassette and compressor sizing necessary to get optimal efficiency out of them. (Letting the HVAC contractor specify the system is almost never the right thing to do.) It's possible to size mini-splits correctly to cover the full load at CT's 99% outside design temperaturers, but if the loads are large it's going to be pretty expensive.

    At CT style electric rates oversizing a ductless solution would be MORE expensive than heating with 82% efficiency gas fired boiler, (but still cheaper than propane or oil).

    Radiant ceilings are cheaper to retrofit than radiant floors, and provide almost as much comfort and heat the whole place (once the house is tightened up), and could be implemented with your existing boiler.

  7. Pagan11460 | | #7

    Hi Dana, thanks again so very much for your response. I'm so happy that I posted on this board. I now have a much better idea of what I need to do. I'll have to find the info/heating bills that you're asking about. And that won't happen until after the holidays. Can I write back to you in January with that?

    Meantime, I would love to have radiant ceilings but what about A/C? If we have a tight house, could we forgo A/C? I mentioned Ray Magic above... they say that you can run both warm and cool water through their system... heating in winter and cooling in summer. But CT is so humid that I've been told we can't do radiant cooling. And we need to cool down this house. I know insulation will help but do you think it's possible to insulate enough that we won't need to cool mechanically? We live in a historic neighborhood and we have three huge oaks that provide lots of shade over our house - two in our front yard and one HUGE one in the back yard but its limbs cause our back yard to be almost covered in shade - add to that fact that our house casts a large shadow in the back yard and we end up with algae growing on our house. We have to powerwash it once or twice a year. We were contemplating taking that big tree out. It's encroaching on our neighbors' yards beside us and behind us. But until we do, if we do, we heard that we shouldn't allow the tree limbs to hang over the roof so that the trees don't damage the roof shingles. We don't want algae and moss and lichen to shorten the life of our roof. (If we could get a metal roof, I'd do it but I think that will be too expensive what with all the other things we need to do.) So we hired someone to come and cut the limbs on the three trees so that none of them hang over the roof now. So... we still have shade from these trees but the limbs are no longer directly over the roof. Would insulation and a tight house - plus some shade from these trees keep out summer heat humidity enough so that we don't need A/C? If so, I'd love radiant ceiling heat.

    Oh hey… hold the phone! As I said, I mentioned Ray Magic above… I just went to the Messana website and the first house in their "Projects" section is in New Canaan, CT. So if they can do it, so can we… except maybe the price might make it unattainable. New Canaan is New Canaan and Waterbury is… well… Waterbury.

    So… how would do you think that we should cool our house if we retrofit radiant heat in our ceilings?

  8. Expert Member
    Dana Dorsett | | #8

    Radiant cooling is difficult to pull off well in CT, but not impossible. It's probably not in the cards if you're on a budget. You'd still have to dehumidify the place by some means, even though the sensible cooling could be radiant.

    Just as with heating , the cooling solution depends on the calculated room-by-room numbers. Generally speaking, the top floor has the higher cooling loads than other floors due to lower shading factors on the windows, and gains through the roof. In an insulated air sealed 2000' two story you may be able get by with just a 1.5 mini-split ceiling cassette at the the top of the stairs at the top of the stairs, but maybe not. If you're going to air seal and insulate at the roof deck (usually a pretty expensive option, but often better), a mini-duct cassette solution up in the attic could do the whole floor. It's silly to try to specify the solutions without the actual load numbers and the layout. There are many options both mini-ducted and ductless that could work, but it's generally better to zone the cooling and heating by floor.

    FYI: The 99% and 1% outside design temperatures for Waterbury are +2F and 85F according to Manual-J:

    Make sure that any load calculations use those numbers, not some 99.7th percential or 0.5 percent numbers. It gets both colder and warmer than that (by quite a bit), but don't start off by calculating the loads at numbers that occur only 1-2 hours out of a typical year.

  9. Pagan11460 | | #9

    Hi again, Dana... I agree with you that it's silly to try to figure it out without crunching the numbers, etc. But this has all been so very helpful in pointing me in the right direction. Thank you to all of you.

    And while it's premature, I like this idea very much... "a mini-duct cassette solution up in the attic could do the whole floor" because I think that - should that work - it would be a reasonable solution. I might be able to find someone with whom to work out a barter... insulation for a website. (I'm a website designer... won a HOBI award a few years ago.) Thank you again to all of you. I need to find myself a weatherization crew or a home performance contractor familiar with blower-door-directed air sealing, like Martin said.

  10. Expert Member
    Dana Dorsett | | #10

    The only way a mini-duct cassette in the attic is going to work efficiency is if the air pressure and insulation boundary is above the ductwork & cassette. That usually means insulating at the roof deck rather than at the attic floor, which is an expensive proposition. But you can sometimes build an air-sealed platform over the top of the cassette & ducts (be sure to leave service access for maintenance) in insulate over the top of the platform with cheap blown cellulose. Most HVAC designers are going to want to run the ducts all the way out to the exterior walls, but you needn't go that far, just make sure the return registers are located at least 8-10' away from the supplies.

    It may be possible to heat the place with a mini-duct as well, if there is a corresponding basement or crawlspace space in which to run ducts for serving the first-floor.

    Most tightened-up and insulated 2x4 construction from the early 20th century ends up with a heat load to floor area ratio of about 15 BTU/hr per square foot of conditioned space, sometimes a bit less. When they're higher than that it's usually a case of higher than usually window area, or an uninsulated foundation. The 1.5 ton Fujitsu mini-duct cassettes are good for about 20,000 BTU/hr @ +17F. A pair of those would probably have you covered down to below 0F as long as they are both fully inside the insulation and air-sealing boundary of the house, and would usually have ample cooling capacity too.

    But we won't know before getting the load numbers on the "after" picture, but how far you actually go on air sealing and insulation makes or breaks this particular option.

  11. Pagan11460 | | #11

    Dana, If I could, I'd name a child after you! But I'm too old to have kids and I'm allergic to cats and dogs. So... I think I'm gonna hafta buy a fish so that I can name it after you! This is all so very helpful. Thank you so very much. (I'll get three fish... one named Dana, one named Martin and one named Stephen.)

  12. user-4053553 | | #12

    Please post their pictures :)

  13. Pagan11460 | | #13

    :) will do!

  14. Expert Member
    Dana Dorsett | | #14

    It would have to be a furry pet frog to have any resemblance to the original... 8-)

    (For the record, I'm NOT the one in red!)

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |