Edited by Eamonn Ryan
Every person has a different opinion regarding the efficacy of various water heating devices, and it is well understood that each depends on site parameters and the compulsory standards related to electric geysers and energy efficiency. SA Affordable Housing asked one such plumber, Leon Raath, for his opinion based on his experiences – though he emphasises this is simply his opinion and not necessarily shared by everyone.
As to how modern electric geysers are more energy-efficient: “According to the manufacturer, the insulation around the steel inner tank is 127% denser than what was previously used. Therefore, it is called a B-grade geyser. According to one manufacturer, all geysers manufactured by them today have the extra thick insulation. (ED comment: the thickness of the tank reduces the allowable heat loss. SANS 151 is currently being reviewed.)
“On older geyser installations, the insulation around the geyser was thinner than today and the hot water pipe from the geyser was typically not insulated. In older houses where the water pipes are galvanised and the bath is cast iron, a lot of heat from the water goes to heating the pipes and bath before the water’s end-use is hot.
“Technology changes all the time. The new geysers, I believe, are more energy-efficient than the older ones. However, water piping, mainly copper, is a good conduit for hot water: very little heat from your water is lost due to the pipe thickness being so thin.”
As to how heat pumps compare to modern geysers: “A hot water geyser may or may not use more electricity than a heat pump. It depends on the size, how much water is used on a daily basis, baths or showers, and most importantly, what piping is used.
“If all the piping in the house is galvanised and the bath is cast iron, you are definitely going to have a hefty electricity bill. On the other hand, if the geyser has a blanket wrapped around it and all the piping is copper, the bath is acrylic, you can cut your electricity consumption to the geyser by up to 50%.
“Heat pumps may save a small amount of electricity but if the insulation around the storage tank (geyser) or pipes is not to standard, then there will not be any savings. Although the manufacturer states a heat pump uses less electricity to heat up the water, one still needs a storage tank (geyser) which makes the cost of the whole installation very expensive.
“Solar heating is the answer: it uses minimal electricity, and then only on overcast days. If the total cost was cheaper to buy and install, I am certain a lot more people would go the solar route. However, at the present price, very little saving will be enjoyed.
How a property developer can assist a consumer to improve the performance of his/her geyser:
- Install a geyser blanket (saving only on the heat loss)
- Consider changing all galvanised piping to copper
- Move the geyser closer to the bathroom
Apply the compulsory requirement in SANS 10400 XA – Energy Efficiency which requires 50% energy to be from alternative sources which is not optional.