ENVIRONMENT & ENERGY
A plumber ’ s viewpoint on energy efficiency
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 energyefficient : “ 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 .
Leon Raath is a qualified red seal plumber drainlayer since 1989 . Having practiced the trade for over 30 years , he has a few lessons and tricks of the trade to share .
www . saaffordablehousing . co . za NOVEMBER - DECEMBER 2020 27