# Questions tagged [water-heating]

raising the temperature of water. For questions about space-heating use the [heating] tag.

22 questions
33 views

### Does a solar thermal hot water system make sense for my home?

Currently my house has a natural gas-burning hot water heater, with a 40 gallon (150 liter) tank. Given the vintage, the efficiency of this heater is likely around 80%. A new, drop-in replacement ...
128 views

### How much energy would it cost to stabilize 2 tons of water at 70 degrees?

I'm trying to figure out the efficiency of energy usage between heating up 2 tons of water from 5°C to 70°C everyday (during winter) within a certain given time (let's say one hour) and stabilizing 2 ...
55k views

### How many kilowatt hours of electricity does it take to heat 180 litres of water from 15 to 60 degrees C?

I think this calculation uses the specific heat capacity for water, which is from memory a bit over 4. Can someone please do the math? Also, if we assume electricity costs \$0.30 per kilowatt hour, ...
192 views

### How can I decarbonise my domestic heating, given severe physical constraints?

tl;dr : For the millions of dwellings that have significant physical constraints imposed by the physical fabric of the building, its configuration and location, that rule out heat pumps, biomass and ...
172 views

### Heating water with compost

We've been experimenting this year with hot composting, and are now looking at how we can go about using the heat generated in the pile to heat water, either to use directly or to pump around as ...
89 views

### on demand water heater - propane vs electric?

We need to replace our (tank) propane water heater. We'd like to switch to a tankless heater, but we're waffling between propane and electric. I saw this question, which was really helpful, but we've ...
2k views

### How to measure the energy output of a thermal solar hot water system?

I have a (thermal) solar hot water system with electric heating, and I'd like to be able to measure the amount of energy provided by just the solar heating. The system is set up like this: Water ...
121 views

### Running boiler intake along chimney for preheating

My house has a boiler in the attic that provides hot water for taps and for central heating. On the opposite side of the attic is a chimney pipe for the fireplace on the ground floor. I was thinking ...
55 views

### Heat escaping very old cob house

I have just moved into a semi-detached house (rented) made out of cob, heated with a wood burner which also heats up the water for radiators and washing. There is also a large boiler,electrically ...
112 views

### How does one calculate the wattage of a biomass fired water heater

My newly designed "biomass fired water heater" gives 50 liters of boiled water within 20 minutes by firing 2kg of firewood. Room temperature is 30 deg. centigrade. Please let me know how to calculate ...
74 views

### Feeding hotwater into modern appliances

Most appliances, such as washing machines and dishwashers typically take cold water and heat it internally. This is probably the most efficient way on a grid connected house with electric water ...
99 views

### Are there different types of water-source heat pump?

I have heard multiple names for water-source heat pumps. What's the difference between something called a water-to-water heat pump, and a seawater heat pump? Are they just different names for the same ...
1k views

### How to cover an open-top shower, to make it feel warmer while showering

There is a product on the local market in New Zealand called "Showerdome" that is a clear plastic dome that can be attached over the top of most open top showers. Covering the top of a shower reduces ...
303 views

### Good alternatives to a fuel oil heating system in an apartment block

I live in a building of 8 apartments, in Belgium. We share a communal fuel oil boiler in the basement to provide hot water and heat. For the latter, each apartment has radiators through which a hot ...
5k views

### Should I worry about the minimum mark on our kettle?

Our electric kettle for boiling water for tea or coffee has what looks like a minimum mark at 0.8 litres (though on closer inspection it says “mini” rather than “min”!). I try to save energy by ...
2k views

### Which is more energy efficient? Heating ten 1L water separately or one 10L water directly

Just like the title said. In my house, we are very heavy tea drinkers. So my mother tends to boil a lot of water every day. She usually does this with a small amount of water (1-2L) every time she ...
445 views

### Pool, sauna and shower with electric heating and solar thermal vs gas heating?

I have four things that need to be heated on my house: Pool (28.000 liters solar thermal heated) Jacuzzi (I think that is like 400-600 liters is gas heated) Showers (actually they are all electric) ...
48 views

### I'm on mains gas and live in England, am I eligible for the domestic RHI?

The domestic Renewable Heat Incentive is about to launch, in different formats, to different constituent countries of the UK. It is an incentive to install particular accredited renewable heat ...
4k views

### How much power does an Electric Airpot use while on standby?

We have just brought a Buffalo K711 4.25L Electric Airpot that is great for my wife as she is disabled and can find a kettle hard to pour. I was expecting it to be well insulated, however its sides ...
1k views

### Forcing water circulation in solar hot water installation

I'm planning an installation for heating water using solar "exchanger" panels (solar used to heat water directly, not through electricity). I don't want to bind the reservoir, panel and tap locations ...