Economy Tip for gas users with combi boilers

  tigertop2 11:54 20 Sep 2008

When getting my gas combi boiler serviced yesterday I learned an interesting tip re saving gas usage. If your combination boiler has a preheater , in effect a programme which switches the boiler's burner on for its small hot water tank intermittently over the day and night, you can get possibly get this facility turned off.
It won't make the slightest difference to the way you use the hot water supply on demand but it does save you money-and probably wear and tear on the boiler system. My combi is a Vokera model but possible others will have the same functions. Mine works perfectly well with the fix.

I am NOT a plumber or central heating expert so consult your local qualified expert. However it is a simple motherboard fix. We need to save every penny we can on utilities these days so I hope this helps someone . Apologies if I am the only guy who did not know about this!

  hssutton 12:06 20 Sep 2008

Must admit to not knowing much about this, but how much water and energy is wasted by this method?

Using a boiler without this preheat tank a great deal of water is wasted whilst the boiler fires up and also until the water temperature is sufficiently warm enough.

  Forum Editor 12:17 20 Sep 2008

have an intelligent preheat mode. This monitors your hot water usage pattern over the previous 24 hours and preheats a short while before the first anticipated use.

This form of preheating is economical and convenient.

  tigertop2 16:09 20 Sep 2008

FE , that is an interesting concept. It would need to have an ET like brain to work out this house's routine!

hssutton, I don't know how much I will save but anecdotal evidence from the guy who serviced my system indicates it might be 5 to 10 %. That is worth having. Just think, if you are out all day and the combi is still preheating it is energy wasted. It also preheats through the night as well just to keep a small tank of water hot.

When I get my next 6 monthly bill I will let you know if there is an appreciable difference

  martd77 19:55 20 Sep 2008

Last winter british gas told my mate if he wanted lower bills to put his combi boiler on the "constant" setting and not on timer setting well when he got his winter bill it was double the previous year!

  Stuartli 20:57 20 Sep 2008

We use gas fires and a radiator in the hall (it only has a tiny flame, yet heats up the hallway, stairs, landing and three bedrooms!), but the greatest cost saving measure we adopted proved to be a multi-valve water heater.

Apart from heating the water on demand just by turning a tap, it is also more than powerful enough to serve the bathroom shower unit without any form of booster.

  hssutton 21:22 20 Sep 2008

My boiler does not have a pre-heater, and often, as I seem to wait an eternity for the hot water to arrive at the tap I have this nagging doubt about the possible hidden expense.

  Forum Editor 23:56 20 Sep 2008

Combi boilers - whether they have a preheat facility or not - are infinitely preferable to a boiler that heats water in a storage cylinder. That method involves the boiler repeatedly firing to hold the stored water at a preset temperature, and you are effectively heating the same water over and over again.

A combi heats on demand, and it only heats the water once - it's a far more efficient method, even if you do have to wait for the dead leg of cold water in the system to be purged.

  pavvi 02:51 21 Sep 2008

You're not alone. I remember getin a leaflet from British Gas giving us the same 'cost effective' solution. We were on token meeter at the time, and when the money in the meter ran out, that was our hot water and heating, oh, and cooking, finished. We spoke to Energywatch (at least that's who I think they were called, and they told us this was the wordt advice we could ever be given. As no matterhow low you have the temperature, the boiler still has to fire up to maintain the temperature....we left Briish Gas prety soon after....

  skeletal 09:55 24 Sep 2008

“That method involves the boiler repeatedly firing to hold the stored water at a preset temperature”. Absolutely, this is why it is important to have a really well insulated hot water tank; the better the insulation, the less heat input you need to maintain the temperature.

On the other hand, if your tank is in the middle of the house, the waste heat will go towards warming the entire house, so it’s not necessarily all lost. The same is true of incandescent light bulbs and the “energy efficient” bulbs; you will save a bit on electricity, but slightly increase gas usage as you’ve lost the bulb’s heat input.

Note: I’m not saying that these measures are not worth doing (particularly in summer when you don’t want the extra heat at all), just that life is a bit more complicated than you think!

Good to see you drop by pavvi...are your vocal cords standing up to the strain of your new life???!!


This thread is now locked and can not be replied to.

Elsewhere on IDG sites

iMac Pro review

Illustrator Charles Williams on how to create magazines and book covers

iMac Pro review

Les meilleures prises CPL (2018)