How to independently calculate water and electric warm floors

Maintaining comfort and energy efficiency in your home all year round requires proper insulation and heating. Water and electric warm floors stand out among the many available heating options for their efficiency and comfort. Even on the coldest days, these systems’ radiant heat creates a comfortable atmosphere by gradually warming your house from the floor up.

Although it is possible to hire experts to install these systems, many homeowners find that doing it themselves is more satisfying and economical. Fortunately, figuring out how much electricity and water warm floors require can be a do-it-yourself task with the correct information and direction.

Before getting too technical, it’s crucial to comprehend the fundamentals of how electric and water heated floors work. Electric systems use heating mats or cables, while water-based systems circulate heated water through pipes buried beneath the floor. By dispersing heat equally over the floor, both techniques eliminate cold spots and offer steady warmth.

There are a number of considerations to make when choosing the dimensions and features of your warm floor system. These include the flooring material, the intended temperature range, the insulation level of the space, and the size of the room or area to be heated. You can determine the precise amount of heating output required and choose the right kind and size of system to install by taking these factors into account.

We’ll walk you through the process of figuring out how much electricity and water your house needs for heated floors in this post. Whether you’re planning a new construction project or remodeling a single room, knowing exactly how to size and design these systems will enable you to quickly and effectively create a cozy and pleasant living area.

Step Description
1 Measure the dimensions of the room where you want to install the warm floor.
2 Calculate the total square footage of the room by multiplying its length by its width.
3 Determine the desired temperature for the floor and the room.
4 Research the wattage requirements for electric warm floors based on the square footage and desired temperature.
5 Choose the appropriate heating cable or mat based on the calculated wattage.
6 Install the electric heating system according to the manufacturer"s instructions.
7 For water warm floors, calculate the heat output required based on the room"s dimensions and desired temperature.
8 Choose the correct pipe spacing and diameter for the water heating system.
9 Install the pipes securely in the floor, ensuring proper spacing and layout.

We find out the required thermal power

Finding out how much Watt of heat is supplied to the heating of a specific room is necessary in order to calculate all the parameters of the future warm floor, whether it be electric or water. We provide the simplest method of determining the necessary heating power, which is by measuring the room’s area or volume.

Suggestions. The cost of installing floor heating contours is high. The cost of the work, including materials and components, is between $5 and $8 per square meter (not including installation and boiler connection). Demand that the performers carry out all calculations if you intend to hire a brigade of masters and you don’t have a heating system project, then compare the outcomes.

We use the drawing’s layout of a modest, one-story home that is 100 m2 (based on the outer measurement) as an example. Keep in mind that during the winter, corner rooms with light openings and external walls will lose a lot more heat than interior spaces like hallways, bathrooms, and corridors. The suggested methodology accounts for the nuance:

  1. By measuring and changing lengths, find out the quadrature of each room.
  2. The areas of rooms with one outer wall and light opening multiply by 0.1 kW. This category also includes central premises (in the example – hallway, bath and corridor).
  3. To heat the rooms located in the corners of the building, you will need to allocate more thermal energy. The quadrature of the room with two external walls and the window should be multiplied by 0.12 kW (kitchen and nursery).
  4. If there are 2 or more window openings in the corner room, the area is multiplied by 0.13 kW (living room and bedroom on the layout).

The computed results are the necessary heat transfer in kW for each room’s heating contours or radiators. After receiving the numbers, you can move on to the next computation step.

Note: These figures are reasonable for the Republic of Belarus and the middle section of the Russian Federation. Thermal power values have to be multiplied by a coefficient of 0.7 for homes in the south. The results are subjected to an increase in coefficient of 1 in the northern regions. 5-2.

For rooms with ceilings higher than three meters, the aforementioned technique is not appropriate. In these situations, the number of rooms multiplied by 35, 40, or 45 watts, depending on where in the building they are, is thought to be the necessary amount of heat. A separate article lays out the specifics of how the heating system’s load is calculated.

Calculation of water heating contours

Once the power of the heat flow required to provide a warm floor in each room has been determined, compute its primary parameters in the following sequence:

  1. Determine the flow rate of the coolant that provides the necessary heat transfer of the contours. Find out and adjust the temperature of the floor surface.
  2. Calculate the step of laying loops, as well as the temperature of the coolant in the supply and back line.
  3. Find out the length of the pipe in the circuit.

We would like to caution against using underfloor heating as the primary and exclusive heating system before performing any additional calculations. Many experts, like Vladimir Sukhorukov, believe that floor heating should be used in conjunction with regular batteries for the following reasons:

  • Water contours warm the decent mass of concrete screed, and therefore quite inert and slowly react to a change in the temperature of the coolant;
  • Radiators are well lend itself to manual and automatic adjustment, quickly respond to the growth or drop in the temperature of network water;
  • To heat the volume of the room without batteries, the pipes must heat the surface to 28-33 ° C, creating a feeling of stuffiness in the room;
  • Accordingly, the coolant will have to be heated to 50-55 ° C, an economical temperature schedule of water floors – 45-35 ° C.

Thus, the advice. Warm floors should be measured at +26 °C, which is the most comfortable surface temperature. In addition, a network of radiators that can run independently of floor heating should be installed. She will support the air in automatic mode and heat it to the appropriate temperature.

You can still use the calculation outlined below to determine the contour meter, the diameter, and the pipeline laying step even if you choose not to install convection heating batteries because doing so will increase construction costs. Our expert’s explanations about radiator installation:

Coolant consumption and coating temperature

The suggested calculation method is based on a visual approach to problem solving. However, in order to properly adjust the distribution collector rotometers, perform hydraulic calculations, and choose the circulation pump based on performance, it is necessary to know the volume of water that passes through the circuit for one hour.

The following formula is used to determine how much heating water is consumed:

  • G – the desired value of the flow, unit of measurement – kg/h;
  • Q is the thermal power consumed on the heating of the room (calculated in the previous section), W;
  • Δt – the difference in the temperature of the coolant in the supply and reverse branch, for the heating floor it is usually taken equal to 10 ° C.

For instance. The 15.75 m² living room will require 15.75 x 130 = 2048 W of heat to be heated. The amount of heated water consumed each hour will be G = 0.86 x 2048 /10 = 176.13 kg/h.

As tiles, linoleum, and wooden parquet (laminate) pass the heat stream differently, you must know the type of coating in order to determine the temperature of the floor’s surface. Let’s say that installing linoleum in the aforementioned living room is the plan. Next, we look at the nomogram, which shows the following parameters:

  • the difference between the average temperature of the coolant and the air of the living room;
  • specific heat transfer with 1 m² of floors;
  • the corresponding surface temperature;
  • Graphs for pipe layout from 10 to 35 cm.

Use the nomogram created for linoleum to find the coating’s degree of heating. When we examine the specific heat transfer, we find that it is greater than 120 W/m2, or 31.5 °C, in the living room. We previously decided that this indicator is excessively large and accepted 26 °C as the ideal value for the computation. In that case, 68 W/m2 is the specific thermal power Q.

Radiators that compensate for heat loss are simple to compute. The found value Q in our example is multiplied by the area of the living room, and the resultant value is derived from the power indicator that was previously calculated: 2048 W – 68 W/m² x 15.75 m² = 977 W.

As a result, the floor system’s coolant consumption will fluctuate. The consumption will drop to 92.1 kg/h, or 0.86 x 1071 /10.

Note: Nomograms are provided throughout the article. Comparable final graphs are assembled for various coating types, such as laminate, thick parquet, and porcelain tile. The "dry" method of floor heating calculations performed on wooden ceilings produces graphs for ceramic tiles.

Laying step and water temperature

The standard for floor heating in private homes and apartments is to install metal-plastic or stitched polyethylene pipes with a 16 x 2 mm (DU10) diameter. The nomograms that are mentioned are specifically made for these types of polymers.

The living room of a one-story house will be used as an example to choose the layout step:

  1. Using the same nomogram composed for a synthetic coating (linoleum), select a graph with an interval of 15 cm.
  2. From the point of intersection of the graph with the green line we fall to the scale of temperature changes, we get TP = 19 ° C.
  3. We find the value of the average temperature of the TSR coolant according to the formula:

The designation TV indicates the ideal temperature for the living room air; we choose +22 °C. TSR is calculated as 19 + 22 = 41 °C. Finding the temperature schedule is simple when you know that there is a 10 degree difference in temperature between the supply and the δT: 41 +/- 5 = 46/36 °C.

Take note: the coolant will need to warm it more vigorously if you choose a wider spacing between the heating pipelines (such as 20 cm). You must maintain 48 °C in the feed line and 38 °C in the reverse.

The temperature schedule computation will aid in the accurate selection of a three-way mixing valve that needs to be mounted on a water collector that is waterproof. Reverse water from the circuits will mix hot coolant from the gas (or other) boiler when it cools to 36 degrees. When the water reaches 46 °C, the pump will force it to rotate along the contours until it cools down again, and the valve will block the feed.

Pipe length and final results

After converting the unit to meters and designing the loop spacing using the Latin letter b, use the following formula to determine the pipe’s length:

The room’s area in square meters is denoted by the letter F. According to our example, the pipe’s length in the living room is L = 15.75 m² / 0.15 m = 105 m. The issue at hand is this: the circuit’s length should not be greater than 100 meters, the hydraulic resistance should be 20 kPa, and the concrete monolith should warm up uniformly. To connect the heating circuit to the comb, the living room must extend 105 meters beyond the length of the carts.

A crucial aspect. Take the location of the closet with the collector and toss in a plan of the house before doing any calculations. The comb is depicted in the drawing as being in the hallway, with each room being roughly the same distance away.

How to fix the problem when there’s a lot of pipe:

  1. Break the area of the living room into 2 heating circuits of the same size.
  2. The length of one pipeline should be determined taking into account the connection to the collector – (105 + 5) / 2 = 55 m.
  3. Make a deformation seam between two monoliths, allowing the slabs to expand from heating without destroying each other.

Pay close attention to the provided scheme in order to correctly pour two plates with a deformation seam. Only the top portion of the "pie," which is a screed with pipes inside, is divided from the base and insulation, which are typically made of foam in monoliths.

Suggestions. It is advised to install RTL thermal tunes on the comb of warm floors in place of an additional pump and a three-way valve if the length of the contours is less than 60 meters. The element restricts the reverse flow’s movement until the coolant’s temperature reaches the predetermined level (36 °C in this case).

The parameters of the floor circuits in the remaining rooms of the one-story house still need to be determined. Assume that ceramic tiles are used in the kitchen, and laminate is used in the bedroom and nursery. We perform calculations and enter the results in the overall table using nomograms for these coatings.

Note: In accordance with sanitary standards, the flooring in the nursery cannot be warmer than 24 °C. The suggested computational method can be found in the 2008 book "Water Heating Systems" by IN. Dersotilova.

Since residents don’t stay in the bathroom all the time, it is preferable to heat it with a resistive cable or mats. Read on to learn how the floor’s electric heating is determined. If you find such computations too difficult, try using the software from reputable heating equipment manufacturers like Valtec and Herz Armaturen. The video displays usage instructions:

Features of electric flooring systems

The technology utilized in the setup and design of electric heaters is distinct from that of water circuit devices and is contingent upon the selected type of heating elements.

  • resistive cables, carbon rods and cable mats are allowed to be laid “dry” (directly under the coating) and “wet” method (under the screed or tile);
  • It is better to use carbon infrared films shown in the photo as a substrate for a coating without filling the screed, although some manufacturers allow laying for tiles.

As a point of reference. Carbon heating elements connected in parallel by two conductors make up self-regulating core systems. Even if one rod burns out, the room will still be heated by the remaining components because of their increased heating power.

Three characteristics of electric heating elements are:

  • uniform heat transfer along the entire length;
  • the intensity of heating and the surface temperature is controlled by a thermostat focusing on the readings of the sensors;
  • intolerance of overheating.

The least desirable feature is the last one. Heat transfer with surrounding air will be disrupted if the circuit is made on the contour site without legs or stationary household appliances. Film and cable systems don’t last long and will overheat. The upcoming video goes over every nuance of this issue:

Self-regulating rods calmly accept such things, but at this point, an additional factor starts to play a role: the irrational purchase and installation of pricey carbon heaters for furniture.

Selection of cable and film heater

In relation to the points mentioned above, the electric heating calculation is made somewhat simpler, and the cable warm floor’s parameters are established as follows:

  1. Calculate the amount of heat necessary for heating a particular room (see section One).
  2. Draw a layout of a room with the location of stationary furniture and household appliances. Draw on a scale to the real size of cabinets, washing machines and so on.
  3. Calculate the free area of the room by taking the quadrature of occupied areas.
  4. The previously found amount of heat should be distributed to the remaining area. Divide the required power into a quadrature of a free section – get a heat transfer with 1 m².
  5. Resistant cables and mats with a thermal power of 9-25 W/m. P. Sold with fixed length. Select a heating element for the required heat transfer to the manufacturer’s catalog.
  6. Divide the quadrature of the free section to the length of the selected product – find out the pitch layout step.

An illustration of how to calculate the area of a one-story building’s bathroom, which is 6 m² and is used for the bathroom, sink, and cabinet in 2.5 m². The free site’s square footage is 3.5 m2, and 600 watts of thermal power are needed. Make your selection of a 37-meter-long, two-core, 622 W heat-transfer Deviflex 18t brand heating cable based on the well-known Devi brand’s catalog. We obtain a step of laying of 0.095 m, rounded to 10 cm, by dividing 3.5 m² by 37 m.

Notably, choosing cable mats is even simpler because the manufacturer designates the space taken up by the heating element. A 635-watt device from the DeVIMAT 200T brand that is intended for quadrature 3 is appropriate for use in a bathroom. 45 square meters.

The film heaters that are positioned beneath the flooring are chosen and calculated. A small detail: a minimum 150 mm indentation is made from the partitions when installing resistive cables or carbon film in the living rooms. It will also be necessary to remove these wall-to-wall stripes from the overall quadrature. This indent is considered to be equal to the styling step (10 cm) in loggias, balconies, and bathrooms.

Budget, pre-existing infrastructure, and individual preferences are just a few of the variables that may influence the decision between water and electric heated floors. Every choice has benefits of its own and things to keep in mind.

Electric warm floors could be the best option for people searching for an affordable and reasonably simple to install solution. Electric systems are a popular option for retrofitting existing homes because they can be installed quickly and efficiently and don’t require a boiler or extensive pipework.

Conversely, water heated floors have the long-term benefit of reduced operating costs. Since a boiler and pipework are required for the installation, it can be more complicated and expensive at first, but over time, water systems use less energy than electric ones, which lowers utility bills.

Room size, insulation, and desired temperature are all important considerations when figuring out how much heat your warm floor system will need. You can make sure that your warm floor system works effectively and efficiently and provides comfortable heating throughout your house by precisely calculating these variables.

Either way, adequate insulation is essential for optimizing energy efficiency and guaranteeing steady heating, whether you go with electric or water heated floors. You can minimize heat loss and lower energy consumption by investing in high-quality insulation materials and installation, which will ultimately result in lower heating costs.

In conclusion, careful planning and calculation are necessary to ensure optimal performance and energy efficiency, regardless of whether you choose electric or water warm floors. To decide which option is best for your home, take into account your heating needs, budget, and the infrastructure that is already in place. And never forget that adequate insulation is essential to reducing energy waste and optimizing the performance of your warm floor system.

The ability to compute water and electric warm floors can have a big impact on how effectively and efficiently you heat your house. Homeowners who can do this on their own will be able to better control their heating systems, which will enhance comfort and possibly result in lower energy costs. Knowing the proper calculations will guarantee that you get the ideal amount of heat for your space without wasting resources, whether you’re thinking about installing an electric or water-based underfloor heating system. Whether you’re heating a room or your entire home, you can customize your heating solution to fit your unique requirements and get warmth where and when you need it most.

Video on the topic

Calculation of the length of the cable for a warm floor

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Michael Kuznetsov

I love to create beauty and comfort with my own hands. In my articles I share tips on warming the house and repairing with my own hands.

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