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Worst Possible System Design - a Path to Redemption?

SeanBoyd
SeanBoyd Member Posts: 1
Greetings, our 28 year old Weil boiler cracked last night and our hand is now forced. 2,800 sq. ft. (~2,000 on first floor over full basement with an ~800 ft. walkout basement apartment in Dutchess County, NY (Zone 6?)) house with said boiler in basement, sending hot water up uninsulated copper pipes to three AC air handlers (3 zones) in poorly insulated, outside the envelope attic, with field hacked heat exchangers tacked on to the ends of said air handlers blowing hot (warmish) air back down through the many-times perforated ceilings to heat the large cathedral ceiling A-frame that is the center of this home and the upper 2-3 feet of airspace in wings that extend out from the center. The only thing that works reasonably well is the baseboard radiant in the basement apartment - reasonably responsive, somewhat efficient. The rest? Well you folks know better than most what a POS this system is. When we bought 10 years ago, I planned to do a staple-up hydronic radiant retrofit, possibly converting to propane to take advantage of an otherwise unused 1,000 gal tank buried outside, and get rid of the 300 gal oil in the precious basement storage area. Never got around to that, but did pull down all of the exposed insulation under the floor in preparation... Yeah, I know...

Anyway, yes propane is far less efficient, but I thought the vastly improved overall efficiency of the radiant design and a modern prop-fired boiled would more than makeup for the difference. 10 years later though, and I am reading all about better sealing, super insulating, etc., (thanks to GBA.com), and I am seriously considering Fuji mini splits to get some blessed relief from the Upstate humidity in summer (did I mention that the air handlers (all 3 of them) were never connected to condensers? - Yes, that's right, this idiotic system, based upon AC design (attic A/Hs blowing down from the ceiling) never was actually usable as an AC system!!! Aargh!!!) But I digress...

I am prepared to get an education in all of my wrong-thinking ways, but due to the urgency of affairs (we have no heat), my thoughts are:

1. Get a new super efficient oil boiler now and connect it to the same stupid hot air system that is in place. (Tired of replacing expensive DHW coils in the old boiler that got gunked up with sediment (from our well pump?), I put in a separate electric heat pump/hybrid water heater (a nice GE) a couple of years ago, and have been happy (now thankful to still have hot water) with that.
2. Forget switching to propane for heating (difficult to plumb into the house for that, might do it later for stoves, to reduce electric load.
3. Get off **** and do the staple up radiant this summer, swinging the hot water over from the new boiler before next heating season.
4. If radiant is insufficient, add mini splits to provide warm air comfort and (finally!!!) some AC for the following summer (we have gone this long, what's another year?).

It seems that radiant has fallen out of favor in the last 10 years, but we do have high ceilings, and I would really like my wife to finally not feel cold down at floor level.

Thank you for reading through to the end, and an even greater thanks for those that can give some advice on whether I am on a reasonable path towards HVAC Redemption.

Comments

  • Zman
    Zman Member Posts: 7,559
    You have quite a bit of work ahead of you. The important part right now is to make good decisions in your replacement boiler selection. First, plug your local fuel prices into this calculator and determine which fuel is most efficient for you.
    www.eia.gov/tools/faqs/heatcalc.xls

    The sizing of your new boiler is very critical. It should be done using a heat loss calculator tool. There are many available online. The values you use in the calculator should be based on the building envelope improvements you are making.

    It sounds like the existing ductwork is hopeless. Ducts in unconditioned spaces are a really bad idea.
    Radiant heat using condensing boilers and low temp water distribution is by far the most comfortable heat source (don't forget cooling) out there. Keep in mind, radiant heating does not have to be high mass infloor. Mr Holladay has an oversimplified view of radiant based on what he sees as the disadvantages of the characteristics one type of infloor heat.
    Radiant can be high mass floors, low mass floors, in wall radiant, in ceiling radiant, high mass cast iron radiators, low mass wall panel radiators, or a combination of all of these, depending on the needs. In areas like yours that need only some cooling, you should be taking a hard look at radiant cooling.

    Step 1, Select the correct boiler for your future needs.(get the heat back on)
    Step 2, Perform room by room heatloss calc.
    Step 3, Design your new heat distribution system based on the calculations.
    Step 4, Perform the building envelope improvements and heat system upgrades.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    RobGRich_49BobbyBoy
  • Rich_49
    Rich_49 Member Posts: 2,766
    Radiant has not fallen out of favor . It seems that in some communities throughout the building trades first cost has become the biggest concern , this by the way is how we got into this ducted mess to begin with .

    I frequent GBA and have a slight building science knowledge also and do not agree . Many of the designs of radiant and hydronic systems that have biased their opinion were poorly done as they still quite often are .

    There are many very good forms of hydronic solutions now that are not as difficult nor costly to install as Radiant . Remember also that radiant does not have to be located in a floor . The building science guys (some) will tell you to use electric , then tell you to use PV with storage . By the time you take these steps you will have spent more of your hard earned dollars and quite possibly have to make many concessions to have done this .

    Air sealing and insulating are both very important . At the end of the day though it still takes 29.3 Kw/h to equal 1 therm (100KBTUh) . Many folks in New England and possibly right around you can attest to the fact that their recommended heat pumps suffered great problems in a winter such as this past one .

    Give us some more information and let us help ..Is your basement finished throughout ?
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833