20. Transition to Electric Heating - NEW SECTION

Individual heat pumps for space heating may not be the right solution for new homes in all situations, for instance where there is no space to locate the heat pump unit in multi-storey buildings and where there are practical limitations on the position and size of emitters.  There are electrically powered alternatives, such as direct electric convection heaters and night-storage heaters that use economy seven electricity, but both of these will, in theory, be more expensive in use than a heat pump as they can be no more than 100% efficient (i.e. one unit of electrical energy is converted to one unit of heat energy).  

Direct electric heating with a combined hot water cylinder and heat pump (in a packaged self-contained unit) is also proving to be an attractive solution in dense flatted developments where there are space limitations and the space heating demand is less than the hot water demand. 

Infrared radiant heating technology is being promoted as being as capable of providing comfortable conditions. Infrared heating is simple to install at low capital cost and, like direct electric, has no moving parts or water carried through the heating system so the replacement and maintenance costs are likely to be comparatively low. The technology is well established but is more usually used in buildings with high ceilings and large heated volumes such as factories, or buildings that are intermittently used for example churches and community halls.  

In contrast to a convective system that warms the air, infrared heating warms the objects and people in a space which in turn radiate heat to warm the air. It is possible to feel the warmth of radiant heat even when the air temperatures are low – the warming experience we get in bright sunshine (radiant heat) on a cold winter’s day. Advocates of radiant heating claim that the warm-up temperatures from cold are much faster than from low temperature wet systems using radiators and underfloor heating.  

There is little documented post-occupancy research on radiant heating in use in occupied homes, though several housing associations are conducting monitored trials for comfort and economy in use. Correct design and sizing of all electric heating, including heat pumps, is essential and there will be challenges as the industry adopts electric heating technologies, as recent research from the Energy House Laboratory Future Homes study has shown. 

One of the potential benefits of some infrared systems is that heat only needs to be applied to the spaces that are occupied, each room can be treated as a separate zone and intelligent control systems can turn the heating on or off by occupancy (via sensors) or on demand. This is likely to be intuitive to most users whereas heat pumps are generally best used to heat the house constantly with a steady input of low temperature heat and all spaces maintained at an even temperature. However, not all manufacturers advocate this approach. 

An infrared heater cannot match the system efficiency of a well set up and operated heat pump, which should achieve coefficients of performance of 3 - 4 for space heating (i.e. one unit of electrical energy delivers four units of heat energy), but this doesn’t necessarily mean that fuel bills with heat pumps will be a quarter of those for infrared heating, and the overall cost (installation, maintenance, replacement and running costs) could be higher for heat pumps over a 50 year period.  

A disadvantage of infrared is that panels need to be optimally placed with no near obstructions, and as the panel surface temperature can be very high they are usually mounted at picture height and above or on the ceiling. 

Things that can go wrong:

• Consumer expectations not fulfilled: electric heating systems may have different heat up times, comfort experience and operation which needs to be explained to the occupier for energy efficient running and comfort; 

• There are innovative IR systems designed to be installed between ceiling/floor joists, behind the plasterboard, as an IR element film mounted on backing boards. These bring risks, if their position is not clearly documented, with potential damage from both follow-on trades and homeowners who could inadvertently damage the heating element. 

Future-proofing recommendations:

• DESIGN: Systems designed for specific house types, also refer to the Microgeneration Certification Scheme (MCS) design standards even though these have been devised for retrofit they identify good practice; 
• INSTALL: Avoid product substitutions and deviations from the design; 
• COMMISSION: Commission all components and the completed system; 
• MAINTAIN: Provide supporting information - through the home user guide to promote an understanding of energy usage including daily and seasonal ‘load shifting’.