Joseph Raftery from Samsung Climate Solutions gives architects the lowdown on the specification and installation of heat pumps
One of the central conundrums to solve in architecture over the next decade will be how our homes can be sustainably built, without compromising on the design aesthetic of the property. The fast-approaching Future Homes Standard of 2025, which will rule out fossil fuel heating in all new build developments, means that there has never been a better time to start incorporating low carbon heating into property designs.
As architectural designer (and brand ambassador for Samsung heat pumps) Charlie Luxton points out, “There are two areas of focus in low carbon buildings: reducing energy consumption in construction and occupation. Any remaining demand for heating or cooling then needs to be met with renewable or low carbon sources.”
“In practice, during construction means using low embodied energy building materials that are long lasting but also designing buildings with a ‘loose fit/long life’ ethos so that they can be easily adapted for different uses over many years. In occupation it means lots of insulation combined with airtightness and optimising for solar gain while mitigating against overheating to drive down heating/cooling and lighting requirements.” Luxton adds: “Finally, heat pumps can be used to provide what heating or cooling is required.”
Rapid innovations rippling through the sector from both an energy efficiency and design perspective, make low carbon heating more viable in both the retrofit and new build architectural space. This innovative method includes taking a fabric first approach to property design, determining the potential heat loss of a building as well as calculating its heat load, to ensure final designs are fitted with appropriate low carbon heating systems.
How do ASHPs work?
An air source heat pump (ASHP) is a low carbon heating system for domestic heating and hot water. Traditional gas boilers operate on fossil fuels whereas ASHPs use electricity and energy available from passing ambient air over a heat exchanger. Energy cannot be created, just exchanged, and heat pumps have a particularly clever way of doing this – the fan takes the energy from the air, uses it to heat a liquid (R32 refrigerant, which has less environmental impact than others) into a gas. This transfers the stored heat energy to heat a home and its hot water tank, then the liquid re-compresses and the cycle repeats.
Why choose a heat pump?
Entirely powered by electricity, when properly maintained an ASHP can be as much as 500% efficient, compared to an average of 92% efficiency for gas heating systems. Typically, for every kW put in at an ambient air temperature of 7 degrees (average for the UK), you would expect to get around 5 kW thermal output to heat a home and its hot water. This COP (coefficient of performance) means in simple terms that the heat output is more than the electricity input; therefore a heat pump can increase the energy efficiency of any home.
As we look towards the future, as the primary source of electricity in the UK shifts in favour of renewables like wind, hydro and solar PV, air source heat pumps offer a viable low carbon option to help the UK meet its ambitious net zero ambitions in the domestic heating sector.
This technology has been around for decades, and is backed by an industry that is driving change and spearheading innovation. As government targets such as the Future Home Standard 2025 and the Heat and Buildings Strategy (October 2021) take effect, complemented by the Boiler Upgrade Scheme for retrofit projects, an architectural focus on low carbon heating can only be a positive development for businesses in this evolving sector.
Key low carbon design considerations
It’s tempting to frame conversations about low carbon heating solutions from a technical or mechanical perspective, but it’s important to consider them from a design point of view too. The latest air source heat pumps are sleeker and more aesthetically pleasing, allowing them to be a feature of a home without disrupting the design. Plus, there are a few different ways in which they can be incorporated, depending on the end design vision.
A heat pump can be accompanied by a hot water tank, but many of these can fit where the traditional tank would sit – in a utility room or airing cupboard. Highly developed control systems, including Wi-Fi kits and apps such as SmartThings, means that homeowners can also monitor their energy use and control a two-zone heating system remotely via a smartphone – while conforming to Part L requirements – in one neat box. This allows low carbon heating systems to blend into homes seamlessly, while offering full flexibility to homeowners in the face of an uncertain energy climate.
Outside of the home, the outdoor unit can be placed in a variety of locations. While floor-mounted on an exterior wall of a property is the most common option, this can be incorporated through a designated area on the side of the house for the unit. Homes can be sustainable, energy efficient and beautiful all at once with this type of innovative heating solution. There are also a variety of other options depending on the build; the outdoor unit can work well on certain roofs with enough flat space, allowing the pipework to go straight down to the tank inside the house. There’s also the possibility of wall mounted units if there is sufficient space on an outside wall without windows or other disruptions.
While low carbon heating systems may seem like a recent development, the technology has long since been proven reliable and more energy efficient than other heating options. Now is the time to develop this into unique design visions for the UK’s future housing stock – not just to help prepare properties for the future, but to leave a positive environmental legacy in everything we build.
Joseph Raftery is heating product manager at Samsung Climate Solutions