Lower water return temperatures are achieved by lowering the hot water supply temperature set point. A return water temperature of 80°F will create the most efficient performance for most condensing boiler systems.
Cold water systems should be maintained, where possible, at a temperature below 20°C. Hot water should be stored at least at 60°C and distributed so that it reaches a temperature of 50°C (55°C in healthcare premises) within 1 minute at the outlets.
Water Heater Temperature Recommendations
The Department of Energy and water heater manufacturers have different opinions. 120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting.
Commercial condensing boilers need a low return water temperature, typically between 80˚F and 120˚F, to condense the hot flue gas and operate efficiently. As the return water temperature rises, the Thermal Efficiency (TE) drops as less of the exhaust gas condenses (see Figure 2 below).
Generally, try and maintain 160oF to 180oF during the winter season, and 120oF to 140oF during the summer season (for non-condensing boilers, the hot water return temperature should not be less than 140oF).
Return of high purity condensate also reduces energy losses due to boiler blowdown. Significant fuel savings occur as most returned condensate is relatively hot (130°F to 225°F), reducing the amount of cold makeup water (50°F to 60°F) that must be heated.
hot water storage cylinders (calorifiers) should store water at 60°C or higher. hot water should be distributed at 50°C or higher (thermostatic mixer valves need to be fitted as close as possible to outlets, where a scald risk is identified)
While there isn't any perfect temperature you should set your HVAC system to, there is an ideal temperature difference between the supply and return air, which should be between 16 and 22 degrees Fahrenheit. This difference in temperature is the evaporator Delta T.
Most gas boilers are set up to operate at what is called 80/60 flow and return temperatures. This means the boiler heats up the water (called 'the flow') to 80°C. The water returns to the boiler after travelling around all your radiators (called 'the return') at 60°C, having given off 20°C to the room.
The best water temperature for radiant floor heating is between 80 and 85 degrees Fahrenheit. While some people argue that you should use water above 85 degrees, operating a boiler at a lower temperature can be just as effective at keeping your home nice and warm, whilst keeping your heating bills at an all-time low.
The best temperature setting for a hot water heater is between 120 and 140 degrees. Below 120 degrees, bacteria can develop in the stagnant water sitting in the tank. Above 140 degrees, the water is so hot that you and your family members can be at risk for scalding in as little as two seconds.
Making sure your water heater is always set to at least 120 degrees minimizes this risk, as the water should be hot enough to kill any bacteria. Even though most units will go up to 160 degrees, you really shouldn't ever set the temperature higher than 140 degrees in order to reduce the risk of scalding.
To do so, he advises, 'Turn your taps on just enough to drip,' and leave them dripping until the temperature outside consistently stays above freezing. This is typically when the weather forecast indicates that the daytime and nighttime temperatures will stay above 32°F (0°C).
An average 40-gallon heater will only take about 30 to 40 minutes to provide heat water, while you can expect hot water from a larger tank (80-gallons) in approximately 60 to 70 minutes. Electric hot water tanks, on the other hand, will take a little longer.
Set too high, or at 140ºF, your water heater can waste anywhere from $36 to $61 annually in standby heat losses. Additional savings will be realized by the lower temperature for consumption (from water demand or use in your home, such as clothes washing, showers, and dishwashing). These may amount to more than $400.
What is a Hot Water Return System? • Per The American Society Of Plumbing Engineers, Domestic Hot Water Recirculation Systems Maintain Domestic Hot Water Supply Temperature By Using A Pump To Continuously Pass Hot Water Through The System And Return It To The Heating Source To Be Reheated.
However, it's best to have a 16 to 22°F difference between your supply air and return air temperature when you set your thermostat. HVAC professionals call this the “evaporator Delta T.” When a temperature difference is within the Delta T, your AC is working properly.
A high return temperature means that the temperature difference across the network ( TFLOW – TRETURN ) will decrease. A smaller temperature difference means pumping more water to deliver the same amount of heat.
Ideal hot water temperature in winter
During the winter months, an optimal temperature for domestic hot water is around 55-60 °C.
What is return temperature? The return temperature is the temperature of the water in the pipe system after heat has been released into the greenhouse. The difference between inlet temperature and return temperature of the water occurs during transport through the heating system.
That will depend. If the AC system is operating correctly, then the air coming out of your vent should be about twenty degrees cooler than the regular temperature inside. So, if you're cooling it and the house is 80 degrees, then you would ideally want the air to be about 60 degrees.
Chilled-water design supply temperature shall be modeled at 44°F and return water temperature at 56°F.
Legionnaires' disease, the pneumonic form, has an incubation period of 2 to 10 days (but up to 16 days has been recorded in some outbreaks). Initially, symptoms are fever, loss of appetite, headache, malaise and lethargy. Some patients may also have muscle pain, diarrhoea and confusion.
The recommended setting for this control is 60°C/140°F. (Storing hot water at temperatures of less than 55°C is not advisable due to potential for Legionnaires disease). If the water coming out of your taps is too hot then check this control as it could be set too high.
The lower you set your flow temperature, the longer it will take to heat your home. It may take some trial and error to find the right flow temperature for your home. Innovation charity Nesta suggests a flow temperature of 60°C or slightly lower if your home is particularly well insulated.