Tips for using hot water wisely

When the weather gets colder, we use more. It is natural that we use more hot water when the weather turns cold and the sun doesn’t warm as much. Still, we can all be mindful and explore ways to save at home. 

Home heating uses 90% of the hot water in the home. There are many opportunities to improve efficiency. Radiators behind sofas or curtains heat only the enclosed space rather than the whole room. 

Radiators should generally be hot at the top and about body temperature at the bottom. This indicates efficient heat transfer. 

Shower or bath? Enjoy a bath if you want—it makes very little difference in total water use. A single average-sized radiator uses the equivalent of six bathtubs of hot water daily. That’s where savings can really make a difference. 

Air out rooms, but don’t heat the whole world. It’s important to air out rooms but avoid trying to heat the outdoors. Do not keep windows open for long during cold weather. An open window above a radiator lets heat escape instead of warming the room. 

Simple actions at home 

Furniture or curtains in front of radiators trap heat and prevent proper air circulation. Move them away so heat can flow freely through the room and reach the thermostat sensor accurately. 

If a radiator is hotter than body temperature at the bottom, it may be set too high or too small for the room. The higher the setting, the more water flows through inefficiently. 

If the radiator doesn’t heat up even after adjusting the setting, the thermostat pin may be stuck. You can remove the thermostat (by pulling gently) and push the pin slightly to loosen it. There are many helpful videos online on how to do this. If it doesn’t work, call a plumber. 

What should you check? 

Radiators that make hissing sounds waste water and should be checked by a plumber. The issue is usually the setting, not the radiator itself. Fixing it quickly pays off. 

Towel radiators are convenient but can easily overheat and waste water, raising bills unnecessarily. 

Knocking sounds in radiators often mean there’s air trapped inside. Release it using a radiator key. The vent plug is usually at the top. Place a container underneath, as water droplets may escape. 

Our comforts 

Hot tubs are a luxury many enjoy at home or in summer cottages. During the coldest months, however, much of the heat escapes quickly, making them inefficient. It’s better to skip using the tub to conserve this limited resource. 

A well-insulated hot tub with a good cover maintains temperature better. If it has continuous water flow, ensure it’s limited. 

Veitur recommends using energy-efficient systems for hot tubs, whether powered by geothermal water or electricity. 

Snow-melting systems can consume a lot of hot water, so monitor their controls carefully to prevent waste. Often, people only notice inefficiency when their bills rise. 

Heat wisely 

Efficient use of hot water starts with a well-functioning and correctly adjusted heating system. 

Ideally, radiators should have air-temperature-controlled valves. These contain small sensors that measure room temperature and adjust the radiator accordingly. When it’s cold outside, they automatically turn up the heat as needed. You shouldn’t need to manually increase the radiator setting. Normally, a mid-range setting (2–3 on most thermostats) is sufficient. If radiators don’t respond to temperature changes, have a plumber inspect the system. 

During cold spells, the water temperature is higher than usual, and radiators set too high can become dangerously hot. 

Rooms with frequent airflow, like entrances or balcony doors, often have radiators controlled by water temperature rather than air temperature. This prevents them from running at full power when doors are opened. These radiators should not be set higher than 2 for optimal efficiency. 

Usage 

Icelandic homes use an average of 4–5 tons of hot water per square meter of housing annually. About 90% of that is for heating, and the rest for bathing, cleaning, and washing dishes. 

To reduce consumption and lower energy bills, focus on how hot water is used for heating. Many factors affect total usage: building size, type, number of occupants, insulation, and heating system settings. On My pages here on our site, you can compare your usage to similar homes or use the table below to estimate consumption. 

Reference table for hot water utilization 

• The coefficient represents tons of water per cubic meter of building volume per year. 

• The lower value corresponds to well-insulated buildings with properly adjusted heating systems. 

• The higher value represents normal usage for buildings in fair condition. 

• To find the building volume, multiply the floor area by 3.3.