Browse Forums Pools & Spas 1 Apr 03, 2013 11:22 am Hey guys Thinking about getting a spa soon and was wondering the heating costs. Lets say i use it mainly on weekends so friday afternoon ill be cranking up the heat to about 38-40 degrees, but keeping it at maybe 20 degrees during the week. Does any one have experience on the additional costs due to this ambient heating? Re: Costs of spa heating 2Apr 03, 2013 4:29 pm inner_westie Hey guys Thinking about getting a spa soon and was wondering the heating costs. Lets say i use it mainly on weekends so friday afternoon ill be cranking up the heat to about 38-40 degrees, but keeping it at maybe 20 degrees during the week. Does any one have experience on the additional costs due to this ambient heating? We keep ours at 32 deg & ramp it up to 38.0 - 38.5 when we use it. Heating from 20.0 to 38.0 would take a long time & probably cost a heap. The new spas now have heat pumps which are supposed to be a lot cheaper to run. I have been meaning to run some tests to see if it's worth keeping it at 38.0 rather than heating a few times a week. I am also thinking of putting a solar panel on the roof to heat the water, circulating every hour or so as the filter kicks in, this might keep it at a reasonable temp. Re: Costs of spa heating 3Apr 04, 2013 5:55 am we have a spa and have timer on it to heat up at certain times of the day due to solar power we have , this way we have had really no extra cost in power. our spa is used everyday Re: Costs of spa heating 4Apr 04, 2013 7:06 pm inner_westie Hey guys Thinking about getting a spa soon and was wondering the heating costs. Lets say i use it mainly on weekends so friday afternoon ill be cranking up the heat to about 38-40 degrees, but keeping it at maybe 20 degrees during the week. Does any one have experience on the additional costs due to this ambient heating? The cost of heating is going to vary based on ALOT of factors like the shape, volume, and surface area of the spa. The heating option that you choose; solar, gas, heat pump. Your location etc. Example; Unheated spa/swimming pool temps in Perth WA vary from about 17 degrees C in the Winter to 29 degrees C in the peak summer. Each time you use the spa at 38-40 degrees, depending on the time of year, you'll be heating the water by between 11 degrees C and 23 degrees C. A typical spa has a water volume of about 1.5m cubed or 1,500 litres. Each litre of water requires 0.00116 kWh of energy to raise by 1 degree C. So, 1500 L will take 1.74 kWh to raise the temp by 1 degrees C. In Summer time when the unheated spa temp is around 29 degrees, it will take 19.14 kWh of energy to heat the spa temp to 40 degrees. In Winter time when the unheated spa temp is around 17 degrees, it will take 40.02 kWh of energy to heat the spa to 40 degrees. So, if using a heat pump with say 400% efficiency, the cost of heating in Summer time will be about $1.15 to get the spa up to temp. In Winter the cost will be more like $2.40. If using a gas heating with say 75% efficiency, the cost in Summer time with be about $3.32, and in Winter it will be about $7. Solar pool heating will struggle to get the temperatures up to 38-40 degrees. But what solar will be great for is raising the initial temperature of the spa, this will save on a lot of the heating costs. If you have a typical spa of say 5m square, and you were to fit solar pool heating panel equal to 150% of the spa surface area. so 7.5m2 square of solar panels. This would raise winter time spa temps to the mid 20's, and the Summer time spa temps to around 30 degrees. Instead of the heat pump or gas heating having to lift the spa water by between 17 and 29 degrees each time, with solar it would only have to lift it between 10 and 15 degrees. So with a heat pump and solar, in Summer the cost would be $1.04 and in Winter it would be $1.57 With Gas and Solar, in Summer the cost would be $3.01 and in Winter it would be $4.52 With Heat Pump & Solar you'll make savings of between 9.5% (Summer) and 52% (Winter) over using just a heat pump alone. With Gas & Solar you'll make savings of between 9.3% (Summer) and 35% (Winter). I'd personally go with a decent sized heat pump and solar - makes a fair difference to the utility bills over a year of use! Re: Costs of spa heating 6Apr 11, 2013 3:12 pm WOW I haven't got a spa I just want to commend you nate89 for the in depth reply you have just posted. Awesome! well done it must have taken ages. I am sure you will help out a lot of people thinking about putting in a spa. Know where your going in life............... you may already be there Re: Costs of spa heating 7May 02, 2013 8:39 am inner_westie Hey guys Thinking about getting a spa soon and was wondering the heating costs. Lets say i use it mainly on weekends so friday afternoon ill be cranking up the heat to about 38-40 degrees, but keeping it at maybe 20 degrees during the week. Does any one have experience on the additional costs due to this ambient heating? hello, jim from roundbathcompany best way to save heating costs=checkout www.sunabsorb.com.au free hotwater for your spapool or swimspa while the sun shines thanks jim Re: Costs of spa heating 8May 02, 2013 12:20 pm roundbathcompany inner_westie Hey guys Thinking about getting a spa soon and was wondering the heating costs. Lets say i use it mainly on weekends so friday afternoon ill be cranking up the heat to about 38-40 degrees, but keeping it at maybe 20 degrees during the week. Does any one have experience on the additional costs due to this ambient heating? hello, jim from roundbathcompany best way to save heating costs=checkout http://www.sunabsorb.com.au free hotwater for your spapool or swimspa while the sun shines thanks jim Hi Jim - looks interesting. Has the unit been tested? Do you have any certifications for the heat output of the unit? - FSEC, SRCC, IAMPO etc? 3 3220 Does anyone have a suggestion for a good hydronic in slab heating speacialist who may be able to help me with an existing system and wether or not it may need a seperator… 0 3431 I am not sure whether Perth has its own way of doing things in regards to this. Most of Perth has class A (sandy soil), except for some areas near rivers or hills. 2 7881 |