Into hot water

With the cost of heat­ing your hot water mak­ing up two-thirds of your elec­tric­ity bill, hot water heat pumps are a great op­tion.

Element - - Home - By Sarah Healy

Heat pump water heaters take heat from the air and trans­fer it to water stored in your hot water cylin­der. This ac­tion is sim­i­lar to a re­frig­er­a­tor, but work­ing in re­verse. The re­frig­er­a­tion process is used to trans­fer low tem­per­a­ture en­ergy to a re­frig­er­a­tion loop, com­press­ing the re­frig­er­ant to a high tem­per­a­ture, and trans­fer­ring this heat to the heat­ing dis­tri­bu­tion sys­tem.

As the co-owner of a thinly in­su­lated weath­er­board home with a young fam­ily, heat­ing and its cost are of­ten dis­cussed. The Hubs and I have weighed the ad­van­tages of en­ergy saver wall panels over a space heat­ing heat pump, in­ves­ti­gated un­der-floor in­su­la­tion and stuffed the low pitched roof with green­fluff (a pitch so low he al­most re­mained additional stuff­ing!). We have, I ad­mit, given scant con­sid­er­a­tion to the heat­ing of our hot water – a ma­jor over­sight con­sid­er­ing the value of hot water to the home and the cost of re­tain­ing vol­umes at a pip­ing 60 de­grees.

It should be a hot topic for all ki­wis as New Zealand places un­par­al­leled re­liance on elec­tric­ity to heat water. A re­port from BRANZ re­vealed that more than 80% of New Zealand homes de­pend on elec­tric­ity for water heat­ing (sec­ond were Aus­tralia and Canada at only 51%). Over­all water heat­ing makes up 34% of res­i­den­tial en­ergy de­mand. Such a suck on the coun­try’s power pro­duc­tion should be a real fo­cus for the govern­ment’s long-term en­ergy strat­egy and, in­deed, EECA through the EN­ER­GY­WISE web­site does of­fer home­own­ers grants from $500 - $1000 for so­lar hot water heat­ing and heat pump water heaters (HPWH).

An ar­ti­cle in Consumer mag­a­zine ad­vised that a good HPWH would re­duce your hot water bill by two-thirds. Ex­trap­o­lated na­tion­ally to a mil­lion homes, this would mean 320,000 tonnes less of CO2 emis­sions per year.

Most of us are fa­mil­iar with so­lar water heat­ing – rooftop panels ab­sorb­ing the sun’s heat – but not the use of a heat pump to do the job. The EN­ER­GY­WISE site uses the anal­ogy of a re­frig­er­a­tor op­er­at­ing in re­verse. The HPWH moves heat from the out­side air into a hot water tank by trans­fer­ring it to a re­frig­er­ant liq­uid. This is pumped via closed cir­cuit through the hot water cylin­der, heat­ing the water. There are two types of HPWHS; In­te­gral and Split. The In­te­gral mod­els com­bine a heat pump and water tank in a sin­gle unit, in­stalled out­doors. This re­moves the cylin­der from your house leav­ing added stor­age space. The Split model uses an out­door pump unit with pipes linked to the ex­ist­ing cylin­der – or a more youth­ful re­place­ment.

It is clear from EN­ER­GY­WISE and the Consumer ar­ti­cle that de­cid­ing which HPWH to buy will be di­rected by your lo­cal cli­mate. David Senn, chair of the NZ Hot Water As­so­ci­a­tion (NZHWA) di­rects pur­chasers to EECA’S web­site for in­for­ma­tion on rel­a­tive per­for­mance and war­ranty, then rec­om­mends con­tact­ing a man­u­fac­turer.

Newspapers in English

Newspapers from New Zealand

© PressReader. All rights reserved.