| An Efficient Radiant Floor Heating System is more than just pipes in the floor |
The Thermostat
- Senses room air temperature.
- Modern thermostats can also sense floor temperature in radiant systems.
- Floor Sensing can be used to limit floor temperature to protect hardwood floors
from overheating or, - Floor Warming can be used to take the chill out of a tile floor.
- Advanced Thermostats will determine cycle rates, monitor recovery rate and
communicate that information to the boiler control. - Improved efficiency & greater comfort are achieved by communication between the
Thermostat and the Boiler Control.
| Tekmar Thermostat |
The Boiler Control
Depending on the type of radiant floor system, water temperature needed to heat the house
at design can be much lower than the water temperature needed with a baseboard system.
The new advanced controls are able to monitor outside temperature, to monitor room
temperature and to monitor boiler temperature. In a multi-zone system, designed with varying
water temperature requirements, the boiler control can raise or lower the water as needed by
zone and adjust the firing rate of the gas burner to match actual heating demand.
What does this mean?
It almost goes without saying, it takes much less energy to heat and maintain water at 100
degrees than it does to maintain water at 170.
And there is an additional Plus. That of improved comfort. When heat input is matched to
demand, swings in room temperature are reduced - the result, improved comfort in the
living space.
Depending on the type of radiant floor system, water temperature needed to heat the house
at design can be much lower than the water temperature needed with a baseboard system.
- Slab, Thin Slab or Engineered metal plated sub floor (70 to 130)
- Under Sub-floor systems with transfer plates (110 to 170)
- Under Sub-floor systems without plates (120 to 180)
- Baseboard is customarily designed at 180 degrees.
The new advanced controls are able to monitor outside temperature, to monitor room
temperature and to monitor boiler temperature. In a multi-zone system, designed with varying
water temperature requirements, the boiler control can raise or lower the water as needed by
zone and adjust the firing rate of the gas burner to match actual heating demand.
What does this mean?
- If outside temperature is 50, the room temperature could be maintained with boiler water
temperature perhaps as low as 70 or 80. - Then as outside temperature drops to zero the boiler water will increase to say 130
depending on the type of floor system.
It almost goes without saying, it takes much less energy to heat and maintain water at 100
degrees than it does to maintain water at 170.
And there is an additional Plus. That of improved comfort. When heat input is matched to
demand, swings in room temperature are reduced - the result, improved comfort in the
living space.
| Tekmar TN4 System Control |
The Boiler
Two basic types of boiler operating designs.
Both types of boilers will work in a radiant system.
However,....If the flue gas temperature is lower, the heat energy not sent out the flue went
somewhere.
How does Non-Condensing vs Condensing relate to radiant floor systems?
Two basic types of boiler operating designs.
- Non-Condensing.
- Flue gases are discharged from the boiler at a temperature high enough (or
enough heat energy is left in the flue gas) such that water molecules remain a
vapor.
- Condensing
- Flue gas temperature is drawn down such that the water vapor turns to a liquid
(additional heat energy is drawn out of the flue gas) before being discharged
from the boiler.
Both types of boilers will work in a radiant system.
However,....If the flue gas temperature is lower, the heat energy not sent out the flue went
somewhere.
- Where?...... To the boiler water heating the house.
How does Non-Condensing vs Condensing relate to radiant floor systems?
- Radiant floor systems, especially the Slab, Thin-slab and Engineered sub floors will
perform within a temperature range of 70 to 130. - A Non-Condensing boiler must produce a supply water temperature above 150/160 so
that the returning water will be above 130/140 minimum required to prevent
condensation within the boiler. Therefore a non-condensing boiler must heat the water
to a temperature hotter than the radiant system needs to prevent condensation. The
water must then be cooled before being allowed to go out to the floor system. - In a Condensing boiler it does not matter what the return water temperature is, in fact
the colder the greater the efficiency. If the floor only requires 80 degree water, the
boiler may only heat the water to 80.
| Munchkin Condensing Boiler & Super-Stor water heater |
| Can Radiant Heating be added to an existing boiler suppling a non- radiant system? Yes |
The pipes in the floor! - Where are they?
The pipes (or Tubing) can be:
Each system has different characteristics. (page bottom)
Some are only applicable to new construction or full renovation not retro fitting (4,5,6,7)
The pipes (or Tubing) can be:
- Suspended under the sub floor - "Suspended Tube System"
- Attached to the underside of the sub floor - "Staple-up System"
- Attached to the underside of the sub floor with metal plates - "Below Floor Plate System"
- Attached above the sub floor, placed between sleepers - "Above Floor Plate System"
- Installed in "Engineered Metal Plate Floor System Panels" which take the place of the sub-floor.
- Installed in "Gypsum Thin-Slab" or a type of concrete poured over the sub floor.
- Installed in "Slab-on-Grade" or tubing run in a concrete slab like the basement floor.
Each system has different characteristics. (page bottom)
Some are only applicable to new construction or full renovation not retro fitting (4,5,6,7)
1. Suspended Tube
(AC - 1) (QM - 2) (AR - 5)
Temp Range 130 to 180
(AC - 1) (QM - 2) (AR - 5)
Temp Range 130 to 180
2. Staple Up
(AC -1) (QM - 2) ( AR - 5)
Temp Range 130 to 180
(AC -1) (QM - 2) ( AR - 5)
Temp Range 130 to 180
3. Below Floor Plates
(AC - 3) (QM - 3) (AR - 4)
Temp Range 110 to 170
(AC - 3) (QM - 3) (AR - 4)
Temp Range 110 to 170
4. Above Floor Plates
(AC - 4) (QM - 2) (AR -3)
Temp Range 85 to 140
(AC - 4) (QM - 2) (AR -3)
Temp Range 85 to 140
5. Engineered Floor Panel
(AC - 5) (QM -3) (AR -1)
Temp Range 80 to 140
(AC - 5) (QM -3) (AR -1)
Temp Range 80 to 140
6. Thin Slab
(AC - 3) (QM - 4) (AR - 2)
Temp Range - 80 to 140
(AC - 3) (QM - 4) (AR - 2)
Temp Range - 80 to 140
7. Slab on Grade
( AC - 1) (QM - 5) (AR - 2)
Temp Range - 80 to 130
( AC - 1) (QM - 5) (AR - 2)
Temp Range - 80 to 130
These Characteristics do not imply good or bad only that there are differences which should be taken into account when designing.
Acceleration (AC) - How fast a floor system will produce a change in room temperature. A floor system rated slow is not a good candidate for
setback of room temperature over short periods of time. Rated slowest (1) to fastest. (5)
Quantity of Thermal Mass.(QM) - How much heat energy can be contained in the floor material. A floor with a the most mass takes a longer
period of time to heat up and will also take a longer period to cool off then one with the least. Result -a more stable room temperature. Rated: (1)
Least to (5) Most
Assembly Resistance - (AR)Like an insulation rating, illustrates how much resistance there is to the movement of the heat energy from the
tubing to space being heating. Higher resistance, more energy must be put in to achieve the required output. Rated (1) Lowest to (5) Highest
(Source: Radiant Panel Association - Radiant Basics Manual)
Acceleration (AC) - How fast a floor system will produce a change in room temperature. A floor system rated slow is not a good candidate for
setback of room temperature over short periods of time. Rated slowest (1) to fastest. (5)
Quantity of Thermal Mass.(QM) - How much heat energy can be contained in the floor material. A floor with a the most mass takes a longer
period of time to heat up and will also take a longer period to cool off then one with the least. Result -a more stable room temperature. Rated: (1)
Least to (5) Most
Assembly Resistance - (AR)Like an insulation rating, illustrates how much resistance there is to the movement of the heat energy from the
tubing to space being heating. Higher resistance, more energy must be put in to achieve the required output. Rated (1) Lowest to (5) Highest
(Source: Radiant Panel Association - Radiant Basics Manual)
Tubing installed in channels of the Aluminum
Heat Transfer plates, stapled to sub floor.
Heat Transfer plates, stapled to sub floor.
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| W.E.Reynolds,L.L.C. Heating Contractor |
| P.O.Box 494, Turner, Maine 207-225-2126 (office & fax) 207-240-1407 (cell) |
| Radiant Heating Technical |
Tubing installed in channels in the sub
floor ( orange lines)
floor ( orange lines)