2020.005 SOLUS+ Radiant Panel Research

  • March 16, 2020
  • andyro

Image Above: SOLUS+ by Koleda, a Switzerland-based engineering company that manufactures in Latvia. The product launched on Indiegogo, and was fully funded in 2019, and is now in full commercial production and sales of their ‘smart’ radiant panel system.

We recently went for a wee drive in the country, and happened upon a sturdy, sensible little building from 1849, the Oro African Methodist Episcopal Church. What struck me was the compact, no-nonsense form, neatly arranged windows with exterior shutters, gutterless eaves that led to a tidy french drain around the perimeter, a solid stone foundation and entry, and notably, a single, central chimney. Presumably a small woodstove sat at the base of that brick chimney, and radiated from the centre of the space to every occupant within, unlike the more fashionable but less inefficient practice of parking a chimney on an exterior wall so as to radiate equally to the exterior and interior of a space. What this building said to me was that economy of energy and material and even labour is paramount, and the spiritual message is one of both simplicity and utility, which in its own right is a kind of beauty. 

But this is a blog about a decidedly 21st century method of radiating heat, and not a 19th century treatment on Methodist heating, although I see the two as related. As emphasized by Science Europe, we must start thinking about Exergy, not Energy when dealing with efficiency. Exergy examines the resource scarcity, entropy and the full production and delivery and ultimate quality and value of energy, together with the efficiency of its end-use. Rather than heating every molecule of air in a volume of a house or room – what if we could specifically target the individual in that room that we are looking to comfort with heat?

That is the overall idea behind the SOLUS+ radiant panel system, by Koleda. Full disclosure, the company provided Thomson Architecture Inc. with 3 of their M1 panels (smaller, $523.30 CAD MSRP) and one of their M2 panels (larger, $677.20 CAD MSRP) for testing and benchmarking. We specify a lot of radiant heating systems. Typically when there is a concrete floor on a project, we recommend radiant in-floor heating. Often this is referred to as radiant ‘hydronic’ heating, because we circulate a water/glycol mix through pipes in the floor to convey heat to the space, and we tie those pipes to an electric boiler to provide the source of heat. But isn’t heating with electricity stupidly expensive, you may ask?

The day our SOLUS+ units arrived, undamaged and on-schedule, ready to deploy.

Yup it is. And typically electricity is priced as much as 7x higher than natural gas for a unit of energy (ekWh), so when a building is leaky and exhausting thermal energy with an envelope full of holes and minimal insulation, together with lousy windows (anything less than triple-panes we consider lousy nowadays), it’s a recipe for big energy bills. But with the zero-carbon buildings we design nowadays, we can reduce these traditional thermal loads or ‘heatloss’ by at least 50%, and on the better buildings by 75% to 95% – the percentage really depends on how terrible the reference building is. We often say a good building can be heated with as little as ‘a candle and a fart’, but carefully, not in that order. When we can substantially reduce the ‘heatloss’, we can heat with electricity and not notice the bite of the energy bills, and the reason we now ‘electrify everything’ is because we can make electricity without burning things that go into the atmosphere by using wind, water and solar energy (WWS), and that puts us on the winning side in the fight against climate collapse.

80% of the buildings we will need in 2030 and beyond are already here now, and we won’t always get the opportunity to make them athletically energy-efficient. Take our mid-century bungalow in Barrie, Ontario as a typical example. As noted in a graph over here: https://www.andythomson.ca/portfolio/2018-011-how-many-miles-per-gallon-does-your-building-get/ We have a decent but not great EUI of 119.54 kWh/m2/yr – about 2x better than most houses. How can a house designed in 1964 be 2x better than a ‘typical’ house built today? Because it has the same compact, rectangular form of our little church example above, and it faces the sun. The GHG footprint of our house is 6.8 tons/yr of CO2e (calculated over here: https://www.andythomson.ca/portfolio/2019-008-teui-calculator-kwh-m2yr/) How can we get that to zero without spending a bag full of cash?

Among strategies to reduce CO2e on a shoestring budget, you have caulking, weatherstripping, smart-thermostats, storm windows and efficient LED lighting, not to mention buying renewable power like Bullfrog power here in Canada. But pretty quickly you run out of options without replacing your windows, furnace, and adding a bunch of new insulation to your house ~ all big capital outlays with long (10yr+) payback times. So without a meaningful price on carbon (by meaningful the IMF suggests $400/ton is in order), there is little incentive, so we need to get really clever.

How it *should* work. The panel connects to your smartphone, but without first connecting to a wifi-enabled sensor, this didn’t work so well for us so we just switched the panels on and off locally as-needed.

What if we dial down our thermostat to 10ºC during the night and periods we are not home, and dial it back up to 18ºC when we are home? Well – we already do the smart thermostat thing, and yeah, our house is often on the cold side of comfortable, which is less than ideal for many folks, especially seniors. So we set January 2020 as a benchmark month, and set out to find ways that we can let the house run at 10ºC more often, and augment the key rooms that we use the most with SOLUS+ panels – and let the panels bring the local temperature and environment up to a comfortable 22ºC.

We fired up three of the four panels that were shipped to use and used them to provide comfort in two key bedrooms and my home office suite. Now I have a number of constructively critical things to say about the panels, but I think most of these can be solved by just simply using the floor-mount feet they company provides. We were shipped the units with the wall-mount brackets which were;

  1. unequal to the slick black look of the panel
  2. mismatched from the template supplied – making mounting an exercise in frustration
  3. the black electrical cord dangles down to the outlet, which is not as pretty as the marketing photos
  4. were shipped with anchors not at all suited for North American gypsum wallboard construction
  5. shipped with a standalone sensor that took an obscure (CR123) battery size (not included) that was;
  6. vexingly complicated to program to the panel and our wifi.

All of that said – I would still recommend the product, read below to find out why. From our study:

Heating degree days (18ºC) in January (our benchmark month before the SOLUS+ units were installed) were 708, and February was 717, so quite comparable as a baseline. I should note, of the 4 panels that were shipped to us, we only managed to install 3 units, and only 2 of these three units was in frequent use, so the study undertaken was only partial, but nevertheless the results were telling. I should mention that the reason we could not deploy all four panels was due to an overly complex process of getting the panel to talk to the standalone sensor units and the panel through our home wifi network. Also, don’t expect the panel to heat the entire room like your furnace does – they are really designed more to feel like you are next to a fire, and so their best effect is from 2′ to 6′ from the position in the room where you spend the most amount of time. I really like this product and hope the company can resolve the connection issues as customers will expect a seamless ‘plug and play’ experience from a tech startup, but if our experience is any indication, without solving this issue, I would imagine a rocky few months for this company from an after-sales support perspective.

The most telling result of the study, a 36% reduction in Natural Gas usage over a nearly identical two months of Winter heating (~700 degree days)

Heating Degree Day Comparison:

  • January 2020 Heating Degree Days: 708
  • February 2020 Heating Degree Days: 717

Electricity Use Comparison:

  • January 2020 Electricity: 1,234 kWh
  • February 2020 Electricity: 1,352.32 kWh (we expected an increase with the units running, but esp. in peak times)
  • January 2020 Natural Gas: 357m3
  • February 2020 Natural Gas: 228m3

Combined Electricity + Gas Utility Costs:

  • January 2020: $296.18
  • February 2020: $268.52

So during our test period, even though our electricity bills rose at peak rates, it was not a significant increase, but the amount of natural gas consumed was only 64% of the benchmark month of January. This has meant a net decrease in our total utility costs of ~10%, or $27.66, but more significantly, a reduced GHGe of 1/4 Metric tons, so from 1.03 Tons CO2e down to 0.72 Metric tons CO2e.

This has likewise resulted in an EUI improvement of ~5 kWh/m2/month. I am confident that if we were able to properly program the panels, we would have seen a ~10kWh/m2/month reduction (up to 40 kWh/m2/yr during the peak Winter heating season) and a more pronounced reduction of our natural gas usage, together with an expected increase in our electricity bills, but with a net reduction in total costs as we saw with this smaller pilot project. The net effect of installing these radiant panels has been that our natural-gas fired furnace simply fired up less often in order to meet a reasonable level of comfort when we were occupying the rooms that the panels were in for the greatest period of time. Less gas furnace, less greenhouse gas emissions.

In conclusion, we saw a net reduction in the cost of our total energy bills of 10%, but more significantly a 36% reduction in our Natural gas consumed, which correlates to a 30% reduction in our GHG impact (when the GHGI of electricity factored into that total reduction at 77gCO2e/kWh).

But is this any more efficient than installing a few baseboard radiant panels in the home and using them the same way, or a fan-based space heater? Yes in my opinion, and here’s why:

  • The panels are large in surface area, to maximize the area of the radiant effect
  • The panels are designed to be aimed at humans, and are not intended to merely heat all of the air in a room – so position them appropriately
  • If you are a renter, you can take these panels with you when you move out
  • The smart thermostat – or at least the potential for a smart app-connected thermostat means you can truly program their time of use most efficiently (even if we resorted most of the time to manually switching them on and off)
  • They are super easy to connect to power – just plug them in and done
  • They look better than a baseboard radiator, especially when they are in white
  • They cost about 1/3rd the cost of a hydronic radiant panel by a company like Runtal with a Danfoss valve and all of the associated plumbing from a central boiler unit.

Recommendation: Buy them if you want to try reducing your gas usage with a smart thermostat, and then augment the spaces you use the most with the SOLUS+ panels, but you may want to wait until the company announces some improvements to their sensors and their mounting hardware. Good luck and happy climate warrioring!


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