I meant the gas-powered instantaneous hot water. They basically use no electricity at all apart from the igniter (you can even get ones that don't require power at all and use water pressure to drive the spark). I understand the point about using excess energy and storing it in another form (like your hot water battery).
The other option is to add an independent solar array just to feed the HWS, but I'm not sure if that would be allowed.
The direct thermal solar collectors are good efficiency, but the required piping and maintenace makes them relatively expensive. With the now relatively low costs for PV panels even wth way with PV and resistive heating the buffer can make more sense. With PV the excess energy can be used, direct solar thermal has usually way to much heat in the summer and still too little in winter.
The direct thermal solar collectors are good efficiency, but the required piping and maintenace makes them relatively expensive. With the now relatively low costs for PV panels even wth way with PV and resistive heating the buffer can make more sense. With PV the excess energy can be used, direct solar thermal has usually way to much heat in the summer and still too little in winter.
Yes, makes no sense for use to waste roof space just for hot water. Might as well put more panels that can power everthing including hot ware, EV, 4 x aircons, stove, oven, dryer, dishwasher etc.
Makes it a no brainer for us to consolidate everthing to electric.
I have been watching the recent videos about the heat pumps and battery storage with interest, as they are both things I have been considering for my own house.
One of things i'd be interested in in how you factor in longevity when evaluating a potential purchase. When i was looking at heat pump based hot water systems previously, the anecdotal evidence seemed to indicate that they often failed around the 5 year mark. Now whether that's true or note, I noted that you calculated the payback period to 7.6 years, but when I looked up the warranty information for Reclaim they had the heat pump listed as 6 years warranty.
So the nett result is that you would run out of warranty before you had reached payback. I have personally always subscribed to the theory that you should reach payback before the warranty expires (otherwise you run the risk of never getting to payback), but I am curious how you view this particular aspect/attribute??
One of things i'd be interested in in how you factor in longevity when evaluating a potential purchase. When i was looking at heat pump based hot water systems previously, the anecdotal evidence seemed to indicate that they often failed around the 5 year mark. Now whether that's true or note, I noted that you calculated the payback period to 7.6 years, but when I looked up the warranty information for Reclaim they had the heat pump listed as 6 years warranty.
So the nett result is that you would run out of warranty before you had reached payback. I have personally always subscribed to the theory that you should reach payback before the warranty expires (otherwise you run the risk of never getting to payback), but I am curious how you view this particular aspect/attribute??
I'd look carefully at possible legionella infections in the hot water pipes; you really need at least 60 deg. C from kettle to tap in order to make sure legionella can't survive. IOW: there is a reason gas heaters are set to rather high temperatures like 90 degrees.
I'd look carefully at possible legionella infections in the hot water pipes; you really need at least 60 deg. C from kettle to tap in order to make sure legionella can't survive. IOW: there is a reason gas heaters are set to rather high temperatures like 90 degrees.
Measured the outlet of my gas tank overflow and it's 53C
But it could have a tempering valve inside, don't know.
I'd look carefully at possible legionella infections in the hot water pipes; you really need at least 60 deg. C from kettle to tap in order to make sure legionella can't survive. IOW: there is a reason gas heaters are set to rather high temperatures like 90 degrees. Recently my youngest son couldn't go to school because they found legionella and had to flush all the water pipes in the building (which is less than a decade old).
Instant gas water heaters, whether the stand alone type or a feature of a combi boiler, only heat the water to 50 degrees or so. I've never heard of one of those leading to a disease problem.
Instant gas water heaters, whether the stand alone type or a feature of a combi boiler, only heat the water to 50 degrees or so. I've never heard of one of those leading to a disease problem.I don't know about practice, but the official guidelines in the UK are 50 degrees or more at the tap, which pretty much means 55 or more at the heater. Here in the Netherlands it's the same, but the guidelines also say >60 at the tap is preferred. Of course at that point you're trading scalding risk against Legionella.
Your water cools 5 degrees in the few metres of pipe between boiler and tap? I think you need to learn about insulation.
The tank will not have a uniform temperature. Chances are, that in the morning the lower end of the tank is quite a bit colder (e.g. more like 25 C). So the amount of hot water / heat will be larger than the calculated 3 kWh. Chances are the actual heat needed is a bit under (e.g. 15% for thermal loss from the off gas) the 12.8 kWh needed for the old gas system. The thermal insulation on the new system likely is also a bit better than for the old one. There was likely some extra thermal loss through the internal Air path were the flame burns.
It is more like coincidence that the electric consumption was also 3 kWh. With a reasonable, though still not great COP of about 3 this would be some 9 kWh.
So it absolutely makes sense to run the heat pump mainly during the day. It may even make sense to shift the time when to run it to later in the day as than the air temperature is usually higher.