Solar Retrofit Part 8: Winter performance

Today (Saturday November 20th) was the first sunny day in a while.  While cleaning up the breakfast dishes I was not surprised to hear the solar pump start.  When I checked I found that my solar tank was down to 20 degrees C, the solar collectors were at 29 degrees C and the outside temperature was minus 17 degrees C.  What did surprise me was that when I left the house to run some errands (around 10:40 AM) I found the collectors were still partially covered in snow! 

Snow covered collectors: Partially obscured flat plate collectors

Snow covered collectors

This mean that my collectors managed to get a 45 degree C differential to the ambient temperature even while partially obscured.  How great is that?

TM_XBS.ca_Collector.pdf119.52 KB

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That's amazing Ken. Especially given the outside temperature.

Yeah, by the end of the day my solar tank was up to 36 degrees.  Not bad for a day that wasn't particularly sunny.

Ken, What brand of Solar Hot Water panels are you using? Jim

I'm using “” flat panel collectors from Taylor Munro Energy Systems. I've attached the data sheet supplied from TMES to the original posting above.

The collectors have no identification plaques on them so I can't tell you where they were made although when I was having my difficulties with TMES (documented here:, I understood that they came from Turkey. As discussed in that posting, TMES is no longer in business.

If I were doing the same project today, I'd try and buy Canadian. Trimline Design ( makes a flat plate collector right here in Edmonton although the price on their web site ($1995) is awfully high.

Thermo-Dynamics ( from Dartmouth, Nova Scotia makes a flat plate collector that lists for $993 including ¾ unions. I'd guess shipping to Edmonton would be $500-$600 but given the collectors are half the price of Trimlines, you'd still be coming out ahead.

Enerworks ( is from Ontario and has one of the highest rated flat plate collectors made. Before I bought my collectors from TMES, I had a quote for Enerworks collectors of $1100 each, not including shipping. Prices may be a bit higher now – unfortunately a quick search did not find any price lists for Enerworks collectors.

Hope that helps.


Ken, Thank for the information. Jim

Based on other things I've shipped, I'd guess less-than-truckload rates for 2 4x8' thermo-dynamics panels would be under $500.

Hi there. A very neat setup. I have an IBC boiler with the same indirect fired HWT. I have zoned radiant in the floors which I have been using. I have not connected the fancoil yet. I now need humidity (my first winter) and am installing a humidifier today on the fancoil. What I would like to know is what did you use for a thermostat that would control 2 sources of heat (fancoil and infloor radiant), the humidity and the A/C in the summer. I build and wired the house myself.

Thank you

I did the installation myself also and took the easy way out: I installed multiple thermostats!  Below is a picture from the main upstairs hallway.  The thermostat on the left controls the radiant floor heating for the kitchen, hallway, diningroom and living room.  The one on the right controls the fancoil.  In addition, there's a thermostat in the master bedroom that controls the RFH for the main floor bedrooms and a thermostat in the basement hallway that controls the RFH for the entire basement.  (My house originally had two furnaces - including one battle-tank unit from 1964 - so I already had two programmable thermostats.)

Each display is in two parts: the right is the currently set temperature (since I took the picture after 8:00 PM, both thermostats had turned down to the nighttime temperature) and the left alternates between the current time and the current temperature.  As you can see, the left side display is not perfectly syncronized between the two.  Finally, the light switch is to turn on the fan - it was already installed when I bought the house and I just left it.

Theoretically, this could lead to the RFH running at the same time the air conditioning is turned on.  In 2007 when I started my renos, I found it pretty much impossible to get someone in to set up everything so I ended up doing it myself.  It looks a bit intimdating but the reality is that we can use the fancoil thermostat and ignore the rest.


Thankyou. So you have the same setup as me. I have thermostats all over for zoned floor heating. In one area on the main floor I have wires for the fancoil and wires for the zone in that area. (Great room/kitchen). I was wondering if there was a single thermostat that would handle it. So two thermostats. I was thinking about that. I also know that A/C could kick in and the other t-stat turn on the heat. LOL Just have to remember to turn the other one off in the spring/fall when that could happen.

Now which thermostat do you want to be dominant? I've got the radiant floor running and we love that. The fan coil can add extra heat for days when temp drops fast. I need the fancoil now for humidity. This is my first winter here and its getting dry. How do you do that. Do you run one type of heat more than the other? Do you use programmable? I was under the understanding that radiant heat is most efficient being set and left alone. Ive checked out that t-stat on the bottom on youtube. Many pros will only install it. I would sure like to just have one t-stat working. On another note. Where is the best place to control A/C from? I have heard inside a bedroom is best as that it the temp you want to sleep at. I have extra wires in MBR in caxe I want to control A/C from there. Where do you control your humidity from?

Thanks Greg


I asked this on Holmes forum and got these two replies,

You really want to check out the the ECOBEE Smart Thermostat, this t-stat will do everything your looking for , and then some.

Any good stat will control radiant as long as you set the heat cycle rate properly. This stat will do almost anything and has up to 4stages of heat and 3 cool and only uses 3 wires! ... 0-9512.pdf (use link on bottom - Greg)
On another note, if you set you fan coil 2 deg higher than the radiant than the radiant will prob never come on. you should reverse the thinking and use a multi stage stat to control both. some guys will tell you it can't be done due to 2 diff systems but it can with isolation relays and a control guy that knows what he is doing.

Wow, you've asked a lot of questions so let me try and address them all.

> which thermostat do you want to be dominant?  Do you run one type of heat more than the other?

I use the fancoil as my dominant source of heat.  I have the fancoil start heating the house first then, after 20 minutes, if the house is still cold the main floor RFH kicks in to help.  The fancoil can only transfer so much heat to which means the boiler typically runs at one-third capacity (or less) so adding in the RFH makes the boiler ramp up its output and heat the house faster.  Once up to normal temperature, it is maintained by the fancoil.

In my installation, the tubing for the basement radiant floor heating is connected directly to the concrete slab and is a seperate load on the boiler.  At the time I did this I had visions of my solar collectors gathering huge amounts of heat during the day during which I would pump it into the slab and have it release at night.  I wanted this seperate from the main floor tubing to avoid overheating the house.  In order to get this, the main floor RFH and the fancoil are connected to the same circuit on the boiler and are controlled via zone valves (including one on the fancoil itself).  My reasoning for the fancoil being the primary thermostat is this:

  • the basement floor takes a looong time to heat up
  • my house was built in 1964 with 2x4 walls and it cools down pretty quickly
  • I need the basement to be a comfortable temperature as there is a downstairs bedroom

> This is my first winter here and its getting dry. How do you do that.  Where do you control your humidity from?

My fancoil is my primary source of heat and has the humidifier that was on the old furnace I took out.  The humidifier is installed on the cold air return with the humidistat also on the cold air return - about 8" above the humidifier.  Yes, this means I have to go downstairs to change the setting.  In reality, once we found a comfortable setting it doesn't change and I haven't touched the humidistat setting yet this winter.

> Do you use programmable?

Yes - for temperature only.  As described above, the fancoil comes on first followed shortly by the RFH.  In addition, I was concerned that using RFH would overshoot the desired temperature so the setting on that thermostat is a couple of degrees lower than the fancoil (although 2 degrees C may be too much of a difference - I'm still evaluating that).

> I was under the understanding that radiant heat is most efficient being set and left alone.

I believe this is true for high-mass (concrete) floors.  My main floor RFH has the tubing stapled up to the underside of the flooring between the floor joists.  As a low-mass floor, it heats up and cools down fairly quickly and so is suitable for a programmable thermostat.

> Where is the best place to control A/C from?

Of all my thermostats, only one is for the fancoil which is where the A/C runs.  My house is a bungalow so I never paid that much attention to the location of the thermostat for A/C.  I don't think bedroom vs hallway is the real concern - it's more likely second floor vs first floor if you're in a two storey.

Thanks for the info on the thermostat options.  Given the different components of my system I figured the easiest, fastest and cheapest way to go was to re-use my existing thermostats and add in another two (for $70 each if I recall correctly).  The ecobee thermostat is an impressive looking unit but I'm not sure it would do everything I need and at $469, it's not exactly inexpensive.



Thank you for all of that information Ken, you have been very helpful.

1 more. I was installing a humidifier a couple of days ago and got out the manual for the blower for my fancoil and A/C coil. It says the blower cabinet must be installed above the A/C coil cabinet. Mine is the other way around. I emailed Goodman who the components were made by and they told me that it MUST be installed as they specified. How is your setup lined up? Right now I have the blower cabinet on the bottom, then the A/C coil cabinet above that, and then the fancoil built into the sheet metal duct above that.


Energy Saving Products makes an optional base for the fancoil which raises it up off the floor which allows for the addition of more substantial furnace filter (I have a 4" thick pleated filter visible behind the bag of cat food in the picture below).  My evaporator is a Lennox unit that was supplied by the "friend of a friend" that I had do my A/C installation.  Here are some pictures...


The Fancoil label (rotated 90 degrees for convenience):


The A/C Evaporator label:


Apologies for taking so long to reply.


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