Thermostat or thermostats for 3 zones of hydronic and forced air
I tried to ask this question at some other places but to my surprise, there was not much response.
Don’t think my situation is unique, so hopefully it will help others too.
With the influx of new, smart, wi-fi enabled or networked, large display, etc. thermostats, I would think that there should be a solution to efficiently control 3 zones of hydronic and forced air, together with dehu and circ. Also, I would love to be able to see the reports, track efficiency, usage, etc.
It’s a 3 level house: basement (hydronic in slab), 1st and 2nd (hydronic under floor) that also has forced air on each of the floors. Trane furnace is a 2 stage model has variable speed DC fan and electronic air cleaner that can circulate at very low speed, all the time. Also, humidifier and dehu/circulator. Hydronic runs through Lochinvar Knight (1 primary, 3 zone pumps, Taco panel)
The goal would be to have 1 centralized thermostat operating everything with remote sensors or 2 thermostats total (1 for each system) I have not touched controls yet. Likely I will decide on Honeywell Tru Zone for forced air, with motorized supply dampers and bypass return damper. Possibly RedLink too, if necessary.
Important note – I don’t plan on running both hydronic and forced air (other than dehu/circ) at the same time. I want to be able to use just 2 stages of forced air heat 3 months a year, 1 stage of forced air cool in the Summer and 1 stage of hydronic in the Winter.
I have looked into Honeywell Prestige IAQ and with proper add-ons, it might be a solution.
Also, read some about Ecobee and it is really impressive. I know I would love it’s reporting feature.
Whether it’s 1 thermostat that does the whole thing, or 1 thermostat for each system, it needs to have zoning/communicating capabilities. Don’t care for hardwired/wireless. I can also see how it’s 3 thermostats – 1 for each floor.
Hopefully someone here had experience with similar situation and can point me to the right direction.
I know it can be done with 6 separate thermostats, but won’t accept that it’s the only good solution in 2013.
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Replies
Nick,
My first reaction is, "Wow! That's a complicated system!" I may sound like a broken record, but my mind always has the same thought: imagine if you had purchased a simpler HVAC system for half the cost of what you bought -- then you could have invested the savings in better windows and more insulation.
I will defer to others on your thermostat question, but it occurs to me that the main advantage of zoning a heating system is so that you can keep different zones at different temperatures. Therefore: 3 zones, 3 thermostats. But I'm guessing that you want to be able to adjust the temperature in your basement without walking down a flight of stairs. Right?
When I built the last house in 2007, my HVAC contractor talked me into using regular programmable thermostat for forced air (1 zone) and 2 plain thermostats for hydronic (2 zones). All easy. But it was 3 story house too and these controls don't do half the job they could, if it was 3 zones all around. The only comfortable places are ones where you have thermostats.
It's not as complicated as you think. 3 story house - so it naturally should be 3 zones. It's not that I would want to have 3 different temperatures. Quite opposite. I want to have 1 temperature on all 3 levels/zones. If it was just 1 thermostat, just the natural stacking of hot air would make the basement several degrees cooler than 2nd floor and 3rd floor would be yet hotter. Horrible.
Well... I inherited the furnace with the house. It has just 3 years of use. AC wasn't even hooked up.
Since new basement slab was poured, it was no brainer to run the pex before the pour. And since I have some experience with hydronic and had it at my previous residence, it all made sense.
Now, back to the thermostats. It's not just the temp. It's humidity (so running dehu and humidifier) and air circulation too (dehu has the exterior air intake and furnace has low speed DC fan).
I can see how 1 thermostat total would do it. I also see how 1 dedicated forced air thermostat would do it. No idea though about 1 thermostat per floor/zone.
I am coming to solution that 3 Ecobee thermostats will work - 1 per zone. There are still questions, like how would I set up the controls, having:
- Trane XV95 2 stage variable speed furnace (feeding out 2 stage control vs time delayed 2nd stage set on the furnace, leaning to full 2 stage control)
- Honeywell True Zone HZ432 zoning panel - probably with DATS (discharge temp sensor)
- 3 Ecobee thermostats (forced heat wired as single stage vs 2 stages)
- 2 to 3 sensors/accessories connected to each thermostat (circ/dehu, slab sensor, return temp sensor, etc.)