Central heating configured for savings


We live in a very cold house.  An early 1900s, single skin brick wall construction house.  When we moved here I didn’t quite realise the problems such a house poses for damp, mould and heating costs.

I am of the ilk who bends the house, or at least tries to, to our lifestyle instead of the other way around.

As part of our refurbishment a couple of years ago I implemented a couple of upgrades to the central heating system of the house:


  1. We installed a highly efficient Baxi Duo-tech combi boiler.  This copes just ok with 2 bathrooms being used at the same time (I think water pressure, or the lack of it, probably just as much contributes to trickle we can sometimes get if two people attempt showering at the same time.  The boiler has done well, coping with extended family staying most of the time and it has stopped working, leaving us in the cold a couple of times too.  I loved the Baxi boiler at our old house, but am sitting on the fence with this one.
  2. I tried to keep as many of the old radiators as possible, knowing that I could save a lot of money on the refurb this way; They are modern ones, but not very efficient ones.  I calculated the cost of new ones and the payback period on the efficiency gain was over 10 years, so decided against changing them.
    Key spaces- the rooms we use most, when we are awake,- have all had new radiators installed. The new radiators are double panel with convectors (those metal strips zig-zagging between the two water filled panels).  I have added thermostatic valves to all except the ones in the lounge/ dining room and the bathrooms.
    The bathroom radiators, I felt were useful to have on anytime the heating was on, not a problem if they heated the rooms are even higher than 20C.  The lounge/ diner didn’t need separate radiator thermostats.
    The radiator thermostats are all set to 20C
  3. Finally we installed a Horstmann digital room thermostat in our lounge/diner (the most used room in the house)  The thermostat has 3 on/off periods per day and is 7 days programmable.  Which in practice means our thermostat is set to:
    • come on at 5.45am on weekdays and warm up the house to 20C;
    • switch off at 9.00am and only switch back on if the temperature drops below 17C;
    • switch back on to warm the house to 20C for lunchtime, between 11.30am and 1pm;
    • then it goes into standby till 3.30pm, when it only switches on if it goes below 18C;
    • finally it prepares the house for when we get back from the school run at a nice 20C and keeps this temperature till 10.30pm.  After this time it allows it to cool to 15C overnight.

The days are programmable all separately and it is very simple to set up.  Our Saturdays allow for a slight lie-in with the heating coming on at 7.30 am and Sundays at 8am.  (With children this is wishful thinking I know!)

If we are away or I am home  and feeling chilly I can easily override the settings and boost the heating or lock it at a certain temperature.

For just over £40 + fitting a room thermostat was a great investment!

This system saves quite a bit of money compared to a traditional system of timer in the boiler.  It also makes the house much more welcoming, having it the right temperature- neither too hot nor too cold- at the times our lifestyle demands.

This is the second house I have installed these and I love it.

Where my system doesn’t work is creating a small warmspot in the house anywhere else than where the room thermostat and thus the main heating controller for the house is located:  Dadonthebrink is always cold in his office upstairs, while I’m feeling just fine down in the lounge.

The other things that has tricked our system is our woodburner, which is installed in the same room as the thermostat.  Often, with the stove on, the room is too hot for the thermostat to realise that the rest of the house needs heating. Leaving it lovely and warm downstairs and rather chilly upstairs.

I’d have 2 options to overcome this: Zoning the central heating system, which involves a controller (i.e. a room thermostat) and a pump for each zone and a fair bit of new pipework.  We did it in our old house, when we gutted it and looked to address the need for additional heating in the basement. It’s a relatively labour intensive exercise and the costs can add up, though I think still worthwhile in bigger houses.

Zoned central heating controls

Here is what hid behind a cupboard in our old house: the three pumps for 3 zones in the house: the basement (a self contained studio), the living zones and the bedrooms. All these could have different settings for times and temperatures for heating. Complicated, but I reckon the cost paid back within a year or two.

The other way, which is what prompted me about the ponderings of our heating set up, is an intelligent system.  At a recent Homebuiling and Renovation Show I saw something along these lines, by one of the energy suppliers, British Gas I think?  Then other day an email hit my inbox about Honeywell, who have come up with an intelligent heating system and a set of  smart controllers, the Evohome.

This is an intelligent system which creates smart zones in your home through special radiator thermostats controlled by a smart hub.

It really appeals to my geeky side: you have a swanky controller, though you can program your system with your smartphone too, and then you have wireless digital radiator controllers to actually control the heat output at room level.

This unit replaces the need for the maze of additional pumps and pipework.

This unit replaces the need for the maze of additional pumps and pipework.

From what I understand, Honeywell’s optimum start technology allows you to set a ‘set point’ temperature at a specific time and evohome works out when to start to get to that point exactly at the right time. Over time, apparently, the Evohome understands how your home heats up and cools down.  So when you want it at 21 Degrees at 7am, it will be perfectly arranged to be that temperature exactly at that time. Evohome dynamically adjusts to the home, so if it is a cooler starting point, then evohome calculates how much to come on earlier, ensuring optimum comfort.

Honeywell’s optimum stop technology applies the same ‘fuzzy logic’ to enable savings on scheduled lower temperature set point. For instance you set at 11pm the home temperature is 18 degrees from 21 degrees in the evening.

With traditional systems the boiler would stop and the residual heat in the central heating would continue to ‘warm’ the home. Even in our system the room temperature reaches the set temperature and the circulating pump switches off, but the temperature will still rise 0.5C or so.

Evohome understands how the home reacts and so efficiently turns the boiler off just at the right time earlier to allow the residual heat in the heating system to be efficiently used, saving energy.  How cool is that!  Apparently, it would save upto £200 on an average household.  Costs: £200 odd pounds and just over £70 for each radiator  controller.  I’m totally fascinated by the concept!  Whether it would be a worthwhile investment in our house?  That’s another issue, especially as we’re not starting from baseline of the average home.

The product becomes available in January and I’ll be looking into the cost benefits in the meantime, especially with the drastically rising energy prices.


How is your heating set up?  Have you installed any clever tools or controllers?


Disclaimer:  This NOT a sponsored post, I have NOT received any incentives or compensation for mentioning any of the technologies I  have mentioned above.   All of the technologies we have installed in our house I do endorse as good products that have stood the test of time.

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