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DIY Radiant Rookie

leegej Member Posts: 30
Hello all,

I’m in the planning stages of a hydronic heat project in my home in central Wisconsin. This project has been in the plans, but now that my wife is eating for two she wants the major home reno projects don’t in the next 9 months. The plan is to put radiant heat under hardwood on 1200-1300 sq ft on the first floor of my home, and baseboard radiators in the 3 rooms of the upstairs. Plan is to have 3 zones: bedroom, living room/dining room/kitchen, and upstairs baseboards, I’ll lay my tubing as such that I can zone things separately later if I want.

I have a plumber/HVAC professional designing the system for me, and he’s pushing the Viega panel system, which looks great compared to the hard way with plates and sleepers I was planning on. We will see what that will cost tho!

I have a Triangle Tube Prestige Solo 110 that’s just hanging on the wall in the milk house, as I sold my dairy herd recently. I live in an old farmhouse, it’s fixed up pretty well but it’s still got the drafts and cold spots of any old farm house. As this suddenly became priority, I haven’t done heat loss calcs, and neither did the guy designing the system actually. The boiler will only be used for heat, not DHW at this point. However I’m pretty confident this boiler will be drastically oversized for the load.

My biggest question on the project is the circ pump(s), zone valves, control, and thermostats. Reading the triangle tube manual it says it can have an outdoor reset hooked to the boiler. I kind of understand the outdoor reset, and everything I read says I want one for efficiency.

I was thinking a Grundfos alpha 2 for the variable speed efficiency , but can I get away with one pump for both in floor and radiant? The boiler is modulating and condensing, so I shouldn’t have to worry about mixing valves as far as the boiler. However I assume I’ll need a mixing valve for the in floor vs baseboard. and on top of it all I like the idea of a smart thermostat (WiFi a plus) to learn the system and improve the efficiency.

This got long winded fast. Long story short: 1200-1400 sq ft infloor radiant in 2 zones. Upstairs baseboards in 3 rooms making 3rd zone. Given my triangle tube modulating/condensing boiler, what pump(s), zone valves, thermostat(s) and controller would work best with overall efficiency in mind.


  • Intplm.
    Intplm. Member Posts: 1,994
    Always a good start to do a heat loss calculation. No matter what you do you must do this otherwise you are throwing good money after bad. It is without question the thing to do FIRST !
    You are doing a reno in a old farm house that has drafts?
    Get the drafts fixed first so you won't have to have a heating system that is "drastically over sized".
    Do it right. Get a heat loss calculation completed first.

    Congratulations to you and yours now that you are expecting.
  • leegej
    leegej Member Posts: 30
    By my calculation: First floor heat loss of 30k BTUH, this is where the in floor heat will be. Second floor heat loss of 20k BTUH, this is where the baseboards will be. I know the house will only get more efficient as I replace some windows this fall and do some foundation and insulation work. The Mrs. wants hardwood immediately, so the new heating system is going in before I can get some of the sealing up done!
  • Zman
    Zman Member Posts: 7,572
    Take your heat loss number for the main floor and look at the Viega system literature to determine the water temps required to meet the load.
    Then size your radiant panels using your heat loss number based on to the same temp. You now have a one temp system. The outdoor reset feature in the boiler will work great.
    Using one circ for both will work if you put a calleffi circuit setter on the radiant heaters so the system will be balanced.
    If you are only doing 2 zones, it would be simpler and cheaper to put a circ on each zone and eliminate the need for zone and balance valves
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein