Frequently Asked Questions
Finding answers when researching hydronic radiant heating systems can be a daunting process. Very few sources speak in laymen’s terms and information tends to focus on the professional builder instead of the home owner. To help we put together a list of the usual questions we get in a simple FAQ format below. Please take a few minutes to click through and suggest questions you wish to have added to this page.
What heat emitters are used in hydronic heating?
- Radiant heated floors and driveways
- Hydronic air handlers and space heaters
- Steel and cast iron radiators and towel warmers
- Baseboard heaters
What information do you need to give me a quote?
- The location and size of the areas to be heated
- The location of the boiler(s) and the distance from the heated areas
- Heat loss calculations if available
- Architectural drawings if available
- Landscape drawings if available
The best way to submit information to us is by using our Quote Request form.
What services does GTAHeat.ca offer?
- BCIN stamped radiant heating designs, heat loss calculations, system audits
- Radiant heating and snow-melt installations
- HVAC design and drawings and installations
- Concrete forming
- Self leveling concrete over-pours
- Gas lines and venting installation
What is the difference between``Floor Heating`` and ``Floor Warming``?
If the primary source of heat is the radiant floor then it is called “Floor Heating”.
If the primary source of heat is something other than the radiant floor (forced air, radiators, baseboard heaters, etc) the radiant floor is considered “Floor Warming”.
What do I need to obtain a building permit?
If you plan to install Floor Heating in the house you need heat loss calculations based on the radiant floor. You will also need loop layout drawings that comes in our heat loss calculations package as well as the mechanical drawings showing the proposed hydronic system to be installed.
If you have Floor Warming you need heat loss calculations, duct layouts that center on the primary source of heat, most often forced air furnaces. You need an HVAC contractor to design and draw those out. We work closely with HVAC professionals and can take care of that side of the installation as well. In this case you do not need to include radiant floor warming in your calculations nor need a permit for that.
Hydronic air handler instead of a gas furnace?
Hydronic air handlers replace gas burners in a forced air system. They heat the forced air using heated water from your high efficiency condensing boiler. You do not need to pay for extra gas lines and venting of a gas furnace and air handlers cost less than a high efficiency gas furnace. We size air handlers so that we can run the boiler at low enough temperature for it to condense. The air handlers we use are multi speed units throttling the fan’s ECM motor up and down as needed to save energy and always deliver optimal air flows.
What can I heat with a boiler?
A system designed from ground up for efficiency and integration will cost less to install and to run than stand alone appliances. A single condensing boiler can heat all your floors, heat your forced air through an air handler, melt the snow on your driveway, heat your garage floor or the air with a hydronic space heater and make domestic hot water with the use of an indirect water heater tank. One integrated hydronic system with a properly sized boiler instead of:
a water heater (gas and vent)
a gas furnace (gas and vent)
a gas garage heater (gas and vent).
Can I install floor heating during a retrofit?
Yes absolutely. A few things to keep in mind.
Unless you are breaking the floor we will lay the tubing on a 1″ thick puck style insulation over which you will have to overpour with self leveling concrete. You will lose anywhere from 2-1/2″ to 3″ from the height of the basement. If you do not use any insulation and tie the tubing to a wire mesh on the existing basement slab you will lose around 1-1/2″ but a lot of heat will radiate downward and be lost.
We staple tubing directly to the exposed plywood sub-floor from above. The tubing is then over-poured with self-leveling concrete to embed the tubing and create a thermal mass that will turn your floors into a giant radiator. All floor plates are either doubled up, or the overpour is done after the rooms are dry-walled so that the drywall can be fastened to wood.
We do not install tubing in joist spaces under the floors. Not one customer we did this type of dry install in the past was happy with the performance of the system. Water temperatures in such installs must be kept very high for the heat to penetrate the floor above and all efficiency of a floor heating system is lost.The added costs of heat transfer plates, insulating the joist space from below, the creaking noises associated with the constant expansion and contraction of the tubing, the heating up of cold domestic water lines etc…
Can I zone floor heating?
Yes absolutely. A couple of things to consider though.
Where the tubing is embedded in the same concrete slab without any thermal breaks between zones the best is to keep the entire basement one zone. Just because you are heating one room 73 °F and the adjacent one to 78 °F heat will radiate sideways and you will end of with one room 75 °F at the edges and 78 °F at the middle, the other with 75 °F at the edge and 73 °F at the middle. If the basement is large enough and has a gym, it makes sense keeping the gym colder than the surrounding areas. For those before the concrete is poured we build a box of flat foam insulation that ends just under the surface around the perimeter. The other usual suspect is a wine room that would have no tubing under it but insulation on the bottom and all sides.
On the upper floors rooms are separated by 2 x 4″ or 2 x 6″ floor plates that are excellent insulators. You can have every single room on a separate zone, independently controlled with a floor sensing thermostat. However… Running tubing to only heat one zone without heating others gets harder and harder the more zones you are adding. With more zones you need more electronics (actuators, wires, transformers, thermostats, zone controllers) and more manifolds adding to the cost of such system greatly. It is recommended that you keep the number of zones to the absolute minimum needed for your comfort. Optimally assign the master bed/bath to one zone, the common areas to another and the rest of the bedrooms to the third zone.
Combi boiler or an indirect heater?
Almost all installations of radiant floor heating systems take advantage of the boiler we install to also make domestic hot water for the home. The two main types of boilers are Combination boilers and Heat Only boilers.
Combi boilers separate the heating and Domestic Hot Waters inside the boiler and prioritize DHW over heating. If your floor is calling for heat but you want to take a shower it would be rather inconvenient having to wait until the floor has reached the temperature to start bathing. At the same time if you are covered with soap and the floor calls, it would be less than ideal if heating got priority and your bathing water dropped to 20 °F or less.
Combi boilers can muster around 4.2 Gallons of hot water a minute, can raise the temperature of the drinking water a max of 100 °F and take time to start up, heat the water and deliver it where it is needed. With a Combi boiler you cannot do DHW recirculation so you always have to waste cold water until the hot one reaches you. Annoying when you wait at the shower, takes forever to fill up a free standing bathtub, not good when your dishwasher gets cold water to wash your greasy pots. Combi boilers are a good idea for small homes because they only burn gas when there is an actual demand for hot water.
Heat only boilers coupled with indirect water heater tanks also prioritize DHW over space heating but space heating will not suffer unless you take 3 hour long showers. Indirect heater tanks if properly sized and coupled to a large enough boiler will not run out of DHW under normal use. Ever. You can recirculate DHW and as soon as you open a tap the hot water is right there. The draw backs are the higher initial cost, the extra space the tank needs and the fact that the water in the tank is kept hot even if there is no need for DHW.
Is a snow melt system expensive?
The price of a snow melt install depends on the size of the area, the brand and model of the boiler used and the distance from the boiler to the snow melt manifolds. Like with many things the more you buy the cheaper you get as systems get scaled up the $/ ft² goes down. To properly quote a system we need to know the answers to the above variables as they greatly affect the installation costs. Please fill out our Quote Request form and you will get a quick and detailed free quote.
Can you do it cheaper?
There are areas where savings can be realized and where they can not be. We can use simpler boilers, install less zones, soldered fittings versus ProPress, lower performing indirect heaters, simpler controls, less efficient circulator pumps. However, we will not compromise the system to come in with a lower quote just to get the job. Cost is a problem if there is no value.
Just how cheap do you want to go?
How much does it cost to run a snow melt system?
The cost of running a snow melt system depends on a number of variables. These are:
- The cost of a unit of energy used (Natural Gas $/m³, Electricity $/kwh, Propane $/L)
- The size of the snow melt area
- The temperature of the air
- The humidity of the air
- Wind speed
- Thickness of the underlying insulation
- The diameter of the tubing in the ground
- The rate of snow fall
- The duration of the snow fall
- The Btu/ft² per hour we are able to deliver to the ground
- The thickness and material of the slab above the tubing
- The drainage of the heated area
All the above variables will dictate how long your snow melt system is operating and and therefore consuming energy. That being said lets look at a 1,000 ft² driveway in the GTA that is well insulated with R10 closed cell insulation from below, well drained using 3/4″ tubing.
Energy usage: 150 Btu/hr X 1,000 ft² =150,000 Btu/hr
Estimated annual hours of operation: 120 hours (historical weather data)
Estimated annual energy usage: 25,000,000 Btu/yr
Fuel: Natural gas
Fuel cost: $0.25/m³
Boiler Efficiency: 95% AFUE
Energy content of natural gas: 36,000 BTU/m³
Cost of energy for 1,000,000 Btu: $0.25/m³ X 1,000,000 = $7,30 CAD
36,000 BTU/m³ X 95%
Cost of 150,000 Btu/hr: $1.10/hour
Cost of fuel for a year: 25, 000,000 Btu X $7.30 = $182.50
How do we prepare the basement or the driveway for radiant heating installation?
In a basement all underground plumbing has to be completed with all pipes under the surface. There can be no hills and valleys because the insulation panels will crack if walked on during tubing laying and the concrete pour. The gravel must be level with the footing around the perimeter so that we can insulate all the way to the outside walls.The thickness of the R10 puck style insulation is 4″ from the bottom to the top with the 1/2″ PEX tubing inserted between the pucks.
Outside for a heated driveway the 4″ thick R10 insulation with 3/4″ PEX tubing is on top of the compacted and graded gravel. On top of the insulation a minimum 6″ concrete must be poured. On top of the concrete you can install flag stone, asphalt or interlocking stones. If interlocking stone is used the compacted screening underlay cannot be more than 1″ thick as it acts as a thermal insulator. Alternately the concrete can be left as the finish surface and stamped to give it a better look. It is crucial to have good drainage for the melt waters not to puddle on the surface.
Staple Up or Staple Down??
A recurring question we are asked is, if we suggest staple down, or staple up (dry) installation of the floor heating tubing?
We always recommend that the tubing is to be stapled down to the sub-floor (plywood) if there is a way. If it is a new construction, staple up should not even be considered. We have never encountered a staple up installation where the client said it met all their expectations and they were happy with the system. There are several fundamental reasons for staying away from a staple up if possible and very few for staying with it.
Pros of a dry install:
- Saves the costs associated with an overpour.
- Weights less than a wet install
Cons of a dry install:
- Required water temperatures must be very high (~140 °F) for the heat to make it through the subfloor. The higher the water temperature required, the lower the boiler’s efficiency. The magic of radiant floor heating is that we get away with low water temperatures (110 °F) and yet heat the space fine. Radiant heat is an ultra comfortable heating system operating our condensing boilers at their optimum efficiency level.
- Every joist space can accept one loop. Sometimes a joist space is already taken up by drains, duct work, electrical and water lines. Floors above those cannot be heated therefore.
- Joist spaces with radiant tubing must be insulated from below by code. It is very difficult or impossible to do so in some cases.
- The high temperature water will not only heat your floor but also your drinking water lines. Getting a glass of cold water from a tap maybe challenging.
- A high temperature joist cavity can make cracking noises when heating up and cooling down.
- Since the tubing is not embedded in concrete there is no “thermal mass” to store the heat. The moment the floor sensor above reaches temperature the thermostat stops the call for heat. Air in the cavity goes cold fast and the floor starts to cool.
- Difficulty zoning. Since there is no thermal breaks between the zones (rooms above), observing zone boundaries is difficult to impossible from below. Joists run in independent directions from room layouts above.
- High labor and material costs (reflective plates, insulation) relative to that of a wet install.
- Low customer satisfaction.