Domestic Water and heating - how do you set yours?

[edge]

Is it more economical to leave the water heated 24/7?

My water is left on 24/7 but heating i just turn it on when i need as the insulation in the house is superb.

 

I found myself leaving the water on all the time as she works shifts and i always used to cock up the settings and someone would end up having a cold shower.

How long will a standard tank hold its heat for?

[Scott]

Ours is timed from 5am till 8am and 3.30pm till 8pm.

 

The thermostat is turned WAY down at night as we don't really need the heating on in the morning unless it is particularly cold. This means that in most instances it is only the water that is heated at this time.

 

My tank takes about 20-30 mins to heat from cold and will last easily 4-5 hours.

[edge]

I was wondering if its cheaper leaving it on all the time or working out how to set it up and doing the timed option?

As when the boiler kicks in it only runs for a minute or two and does this about every hour or so.

Or would it work out the same?

[The Raven]

Self condense combi oil boiler FTW.

 

The hot water is on all the time as it only fires when its called for. The stat is on a toasty 20 again the boiler only fires when hot water is needed then turns off.

 

No tanks

[Scott]

I was wondering if its cheaper leaving it on all the time or working out how to set it up and doing the timed option?

As when the boiler kicks in it only runs for a minute or two and does this about every hour or so.

Or would it work out the same?

 

I have read in the Winter that it is better to keep it on at a low setting all of the time. The obvious reason for this is to prevent burst pipes but the other reason is down to the amount of energy required to get your water from freezing cold to normal temperature. It allegedly costs more to go from freezing to operating temp than it does to keep at a constant lower temp and only increase when required.

 

When it is freezing I leave the heating on at a very very low setting for those very reasons.

 

Do you have a meter? it won't be 100% accurate but you could do a week of both and see what uses the most units.

[Terminator]

It is more efficient to maintain a steady temperature rather than keep going from high to low. To really see any benefits you need a temperature compensation system. It measures the rate at which your house looses heat. It then uses the outside temperature and inside temperate and then applies only enough heat to maintain the temperature you want in the house. I have been using such a system for since 1986 saved me £1000's.

[j_jza80]

Self condense combi oil boiler FTW.

 

The hot water is on all the time as it only fires when its called for. The stat is on a toasty 20 again the boiler only fires when hot water is needed then turns off.

 

No tanks

 

Hot water flow rates are crap compared to a conventional pumped/unvented system though. Not so important with regular showers etc but the difference can be massive with decent stuff. I wont even go into filling baths...

 

I used to specify boilers to Heating engineers / plumbers daily and very rarely recommend combi systems for anything other than 1 bed flats.

[edge]

It is more efficient to maintain a steady temperature rather than keep going from high to low. To really see any benefits you need a temperature compensation system. It measures the rate at which your house looses heat. It then uses the outside temperature and inside temperate and then applies only enough heat to maintain the temperature you want in the house. I have been using such a system for since 1986 saved me £1000's.

 

These compensating system thingys? Can they be added to my normal gravity fed system?

Is it just a few sensors and control unit?

[Terminator]

I think many boiler manufacturers are fitting temp comp systems to some of their boiler ranges. My system is not available any more, it was too far ahead of its time. Honeywell withdrew it because they had too many call backs to domestic settings. Basically punters could not cope with a heating system that sometimes had relatively low water temps in radiators, so they thought the system had faults. Everyone expects red hot radiators when the heating is on. My system only works at max boiler temperature during the really cold weather. The other day when we hit 7 degrees outside the water in the radiators was 55 degrees, compared to the 82 degrees when it was blowing a blizzard. Later in the spring the water in the rads will only be 40 to 45 degrees, gradually as the weather gets warmer the circulating temperature will drop lower and lower until the rads are barely warm to touch. Once the out side temperature gets within two degree of my chosen minimum temperature, 18 degrees, the heating will shut down. Once the system was set up I never touched it again, I leave it on all year and let the computer take over, so if we get a sudden cold spell, we don't have to decide if we what to put the heating on. The system helps save energy in other ways too. When I first set it up it took three days for the system to learn the U value of the house (the rate of heat loss). From then on, it knew how much heat to put into the house to match the heat loss and keep the house at the temperate we chose for comfort at various times of day. This has another advantage, in cold weather the system can fire up, up to 3 hours before we want the house to be at say 21 degrees by 6.45 am, so no matter what the weather, when we get up the house is as warm as we want it to be. At the other end of the day, it knows how much heat it needs to keep our desired temperature for, say 11.30 pm, so it can shut the boiler down an hour or two before hand,but keep the water circulating round the system. You also save energy because unlike a conventional system it won't be firing the boiler when the maximum room temperature is reached, leaving all that heat energy wasted in the boiler it will pump the water round to distribute the heat.

 

If anyone is having a major up grade of a heating system, I would whole heartedly recommend getting the best control system you can afford. If you are replacing a basic on off thermostat control system, you will save around £350 a year on gas bills in a fairly large 4 bed house in the first year. I fitted my system back in 1996 it cost £196, which was a lot compared with a basic room stat system and it has paid for itself many times over I think if I had not replaced it and kept the basic room stat system, I would have spent £4.5k+ more on my gas bills since 96.

 

To go back to the original question, my physics is a bit rusty, but I am pretty sure it requires more heat energy to get a body to temperature, than it does to maintain that temperature. So it is better to reduce the gap between the highest and lowest temperatures you have in the house. My low figure is18 degrees but it rarely drops to that.

[JustGav]

At the moment, mine is on fuzzy logic and it is nothing to do with my home automation setup either... it has failed under contionous testing and turns on when it wants, usually at 3 in the morning roasting the bedroom and off at 7 so the house is cold for the morning...grrrr