Can you use tankless water heater for radiant heat

By Victoria Simmons March 12, 2026

Though they are sold primarily for domestic hot water, tankless heaters are actually well-suited for radiant heating, which operates at low temperatures compared with, for example, hot-water baseboard. So using the unit for radiant heating generally has little or no effect on the sizing calculation.

Can you run radiant heat with a tankless water heater?

Though they are sold primarily for domestic hot water, tankless heaters are actually well-suited for radiant heating, which operates at low temperatures compared with, for example, hot-water baseboard. So using the unit for radiant heating generally has little or no effect on the sizing calculation.

Can you use a water heater for Infloor heat?

Water heaters, on the other hand, are perfectly happy being fed 55°F supply water and chugging along at 110°F to 140°F — perfect for radiant floors, and more than adequate for many baseboard and panel radiator applications.

Can a tankless water heater be used to heat a house?

Many people look at these small appliances and think, “Why can’t I use one to heat my house?” The answer is, you can. … It’s true that a tankless water heater can easily heat most single-family homes. It’s also true that a tankless water heater is smaller and less expensive than a boiler or a furnace.

What is the downside of a tankless water heater?

The main disadvantage of tankless water heaters is their upfront cost (unit and installation) is significantly higher than tank-style heaters. Including installation, tankless water heaters cost 3 times more than tank-style water heaters on average. … they cannot provide hot water during a power outage.

Do tankless water heaters have thermostats?

Tankless water heaters have adjustable thermostats. The thermostat may be inside or outside the water heater’s housing, depending on the system’s make and model. If you have a modern water heater, it may also have a digital display of the set temperature. … An accidental knock can inadvertently move the thermostat.

Can I use a tankless water heater as a boiler?

Can a Tankless Water Heater replace my boiler? Absolutely! Not only can you install a Tankless ASME Boiler, but with a Combi System the same unit can be used for domestic hot water as well. Not all Tankless Units are considered boilers, so make sure to look for a unit with an ASME.

Is a tankless water heater worth the cost?

While month-to-month water heating costs are cheaper with a tankless unit, it could take years to make up for the high initial cost. Over time, a homeowner will likely come out ahead, but according to Consumer Reports, the energy savings for going tankless add up to $75 per year, on average.

Should I turn off tankless water heater if water is off?

Tankless and point-of-use water heaters do not need to be shut off in any case to a water shutoff, as they do not run heating elements continuously or hold water in a storage tank.

How hot is the water in radiant floor heating?

Hydronic radiant heating systems are usually designed to heat an entire house. Water is heated to between 100 and 120 degrees Fahrenheit by a boiler and circulated through tubing under floors.

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What size boiler do I need for radiant heat?

Boiler Capacity An easy rule-of-thumb for BTU requirements is to figure that you need about 50 BTU per square foot of interior space in a cold climate; 35 BTU per square foot in a moderate climate; and 20 BTU per square foot in a hot climate.

How hot should radiant floor heat be?

typical operating temperature range for radiant floor heating systems at 85-140 °F (30-60C) though we agree that 140 deg. f. is a bit higher than suggested by other sources.

Are tankless water heaters loud?

Tankless water heaters will all make some noise when starting up and heating water, but the noise levels are usually reasonable and not cause for concern. … Other sources of noise include blocked or inadequate ventilation or a defective or improperly set pressure valve.

Can a tankless water heater freeze?

Still, the tankless hot water heater can freeze if certain precautions are not taken when the temperatures drop below a certain level. Most indoor and outdoor tankless water heaters have built-in freeze protection against temporary winter temperatures ranging from -5 degrees Fahrenheit to -22 degrees Fahrenheit.

Do tankless water heaters have endless hot water?

Tankless water heaters — also known as instantaneous or demand systems — provide hot water only when necessary. … In contrast, a tankless heater can provide unlimited hot water because it maintains 2-8 gallons per minute (gpm) of hot water as long as water is flowing through it.

How long do tankless water heaters last?

Most tankless water heaters have a life expectancy of more than 20 years. They also have easily replaceable parts that may extend their life by many more years. In contrast, storage water heaters last 10–15 years.

Is radiant heat a closed system?

In a Closed Radiant System, the heating fluid is self contained. The fluid stays there unless removed for maintenance. The closed system and the potable domestic water source are not connected. A baseboard heating system using a boiler is one example of a closed system.

How does a tankless hot water heater work?

Tankless water heaters work by using an electric element or gas burner to warm the water as it travels through a pipe and into the unit. This delivers a near endless supply of hot water and provides instantaneous comfort and convenience. Unlike traditional water heaters, the hot water supply is not stored in the tank.

How hot can tankless water heaters get?

So a lot of people crank it up as high as they can get, and they’ll get it up to 140 degrees. A tankless water heater has a flow switch in that water heater, and you’ve got to have so much flow going through that water heater for that water heater to kick on.

What is the best temperature to set a tankless water heater?

You’ll want to shoot for 100-115 degrees Fahrenheit for your water to be heated. If your groundwater temperature is 60 degrees and you want your shower at 110 degrees, that’s going to be a 50-degree rise.

What maintenance is required on a tankless water heater?

Flushing the System. The hot water heater should be flushed at least once a year. …
Cleaning the Air Filter. In your tankless water heater, there is an air filter that will need to be cleaned regularly. …
Cleaning the Water Filter. …
Cleaning the Tank.

How do I keep my tankless water heater from freezing outside?

Install Your Water Heater in a Warm Place. …
Drain Your Water Heater. …
Maintain a Power Source. …
Consider a Recirculation System. …
Insulate, Insulate, Insulate. …
Run a Trickle of Water.

How often do you flush tankless water heater?

Over time, a tankless water heater may accumulate mineral build up which can erode the walls inside your tank’s heating chamber. To properly maintain and clean your tankless water heater, it’s important to flush those mineral deposits at least once a year.

Do gas tankless hot water heaters need electricity?

No, a tankless gas water heater still requires some electricity to operate. Tankless gas water heaters have an internal PC board, electronic ignition, and an electronic thermostat that requires electricity to operate.

How much do plumbers charge to install a tankless water heater?

The average hourly rate for a plumber to install a tankless water heater falls between $45 and $150 per hour. Final labor totals average between$100 to $450.

How much does it cost to install a tankless water heater from Home Depot?

The Home Depot offers traditional water heater tanks and modern tankless units, both powered by either gas or electricity. Depending on your selection, the average cost for water heater installation is between $1,000 to $3,000.

Can you install a tankless water heater yourself?

Installation. While it is possible to install your own tankless water heater, it’s not a job for inexperienced do-it-yourselfers. There are a number of different sizes and styles of tankless water heaters, including propane, natural gas and electric, along with single-room or whole-house sized models.

How do you insulate a slab of radiant heat?

Once the vapor barrier is in, you should insulate the slab from the earth. Extruded or expanded polystyrene (rigid blue or pink board) is the material of choice. Typically, we recommended 2″ but some states now require 3″ or R-15. Some promote the use of thin sheets of foil/bubble or an insulating blanket.

What kind of boiler do I need for underfloor heating?

Underfloor heating water systems are made to be used with heat pumps as they require only a very low water temperature. The best boiler to use is a condensing boiler as they are very efficient. A condensing boiler works by using the latent heat created using another heat exchanger fitted within.

Should I turn off radiant floor heating in summer?

In summer though, you won’t be needing it. How do you ensure your underfloor heating system or radiators are ready to go when winter comes back around? As a general rule, you don’t need to turn the boiler off. You can control the heating system from the central heating thermostats.

How do you build a radiant heat system?

ESTIMATE YOUR HEATING REQUIREMENTS. …
DETERMINE THE HEATING REQUIREMENTS PER SQUARE FOOT. …
MULTIPLY HEAT LOSS BY TEMPERATURE DIFFERENCE. …
DETERMINE YOUR HEAT OUTPUT. …
WHAT SHOULD YOU DO IF YOU ARE NOT SURE THAT YOU WILL GET ENOUGH HEAT FROM THE RADIANT FLOOR? …
MAXIMUM FLOOR TEMPERATURES.