Energy Efficiency

When temperatures drop, heating bills rise! Plug in to new ways to stay sustainably warm.

Looking for better ways to heat up human habitations is as old as civilization itself. Central heating – more efficient than simply heating a small space with an open fire – was already being used by ancient cultures such as the Greeks, Romans, and the Umayyad Caliphate.

In cold climates, proper heating is essential for everything from quality of life and health to productivity at work. Growing concern with lowering the cost and the environmental impact are fueling new ways to do both. UH looks at both traditional ways and some of the latest trends.

Energy Efficiency
Keeping the energy in and waste out – Energy efficiency combines educating people about consumption with new, improved, and green building construction that reduces an urban center’s environmental footprint.

Published on 11.01.2018

Traditional ways to beat the cold

Some of the new technology is exciting, but the growing importance of sustainability has also meant that a very old rule of staying warm is making a comeback: “first warm the person, then warm the room.” For little or no investment, you can easily warm up, and even have fun while doing it.

DIY home heating – low cost and high effect

One obvious way to have a warm home is to live in a city! Cities are warmer than rural areas with the city acting as a “heat island” in a sea of cold. Multi-family urban dwellings are also more efficient. Apartments have fewer external walls and benefit from the heat of neighboring flats. Avoid top floors though: they lose more heat through the ceiling, although a black roof helps by collecting daytime heat.


Infrared picture of Zagreb during night

A rooftop garden also provides excellent insulation, as well as other benefits. Triple-glazed windows, weather-stripping, increased thermal home insulation, and ceiling fans in reverse setting also work well.

Renewable heat – technology on the cutting edge

High technology offers many sustainable ways to keep you warm. For instance, a smart thermostat is a low-cost way to improve the efficiency of your existing heating system. Larger scale methods include using renewable energy to power the heat, e.g. solar, or upgraded biomass gas, as well as sustainable heat distribution and construction techniques.

Another option is to use renewable heat directly, as in geothermal heating. Reykjavik has been using geothermal heating for decades. In fact, 90% of Iceland’s buildings use this method, including the floors of parking lots and even roads (to keep them ice-free). The same geological activity that keeps Icelandic volcanoes smoking is also used to sustainably improve urban – and national – quality of life.

But even volcano-free cities can benefit from geothermal heating. Using water or ground-source heat pumps, cities can use the heat generated from temperature fluctuations in the water and soil around them. Glasgow has been experimenting with doing this in flooded mines and the Kelvin River. Stockholm boasts the world’s largest seawater heat pump.

How does a ground-source heat pump work? Simply.

Sustainable distribution – district heating

It’s not exactly the top tourist attraction in Copenhagen but it should be: the 1,500 km long distributed (district) heating system that meets nearly 100% of the city’s heating needs. District heating centralizes heating production and distributes it along networks of underground pipes – reducing both the carbon footprint and energy production costs.

The Copenhagen system uses cogeneration – using bi-product thermal energy – from combined heat and power (CHP) plants as well as from waste-incineration plants. These provide greater efficiencies, reducing fuel consumption by 30%, and better pollution control, with half the CO2 emissions.

Helsinki has a similarly extensive district heating system, which set a new record in 2016 for demand: 2,650 MW, roughly the same as 30 large passenger airplanes need for takeoff. What made it possible to meet that demand was the use of “heat accumulators,” in this case gigantic water tanks that effectively store unused heat until it is needed.


Energy efficient construction – passive buildings

Although there are many ways to increase the energy efficiency of a building, the Passive House Standard has emerged as one of the leaders. Originally based on new construction pioneered in the 1970s in North America, the idea has achieved its greatest success in Scandinavia and Germany.

The “Passivhaus” incorporates a number of techniques, but the most essential feature is the use of airtight super-insulation together with sophisticated ventilation. These can be combined with passive solar energy techniques, repurposed waste heat (e.g. from lighting and cooking), and energy-efficient landscaping to reduce energy consumption by up to 90%

As the price of building a passive house has gone down, its adoption has increased. Frankfurt boasts 600,000 m² of passive housing, and all new buildings owned by the city or its public housing association must be built to the Passivhaus Standard. Dublin has gone a step further – ALL new buildings there must meet that – or an equivalent – standard.

Warming up to the cold

Like many environmentally friendly technologies, passive buildings and renewable and district heating offer only good things: lower costs for consumers, better care for the planet, and plenty of new heart-warming business opportunities for urban cold-climate entrepreneurs.

Even in the dead of winter, cities are alive with possibilities. What is your city doing to keep away the chill? What’s your “hot tip” for staying warm and cozy? Let us know!