Energy myth-busting: Is it cheaper to have heating on all day?

richardc1983

zeupater wrote: »

Hi

Yet I've seen first hand the effect of installing a small (£300?) single room MHRV solution in an upstairs bathroom has on an entire house when leaving doors open ... much of the humidity that exists in a house results from the occupants breathing when asleep in rooms where temperatures and conditions may be atypical to the entire property - as bedrooms are normally close to bathrooms a single-room MHRV can often suffice, it just depends on the property & severity of the issue.

HTH
Z

yes I found that if the MHRV was in a single bathroom I found it to short cycle the air, yes overall it will eventually do the whole house but for me the PIV is better as it pushes air slowly and gradually through the entire house and I can train the air to go where I need it to.

zeupater

richardc1983 wrote: »

yes I found that if the MHRV was in a single bathroom I found it to short cycle the air, yes overall it will eventually do the whole house but for me the PIV is better as it pushes air slowly and gradually through the entire house and I can train the air to go where I need it to.

Hi

With the obvious acceptance that for every cubic metre of external air injection into the house, an equivalent volume of heated air is expelled.

In terms of this thread, the act of expelling warm air removes energy which needs to be replaced with the only resultant being an increase in the need to address the heat balance through cycling the heat source either more intensively or more regularly.

Regarding the training of passive internal airflow - this really applies to all air in a house, whatever form of ventilation exists .... that's what opening doors and having differential temperatures does!

HTH
Z

richardc1983

zeupater wrote: »

Hi

With the obvious acceptance that for every cubic metre of external air injection into the house, an equivalent volume of heated air is expelled.

In terms of this thread, the act of expelling warm air removes energy which needs to be replaced with the only resultant being an increase in the need to address the heat balance through cycling the heat source either more intensively or more regularly.

Regarding the training of passive internal airflow - this really applies to all air in a house, whatever form of ventilation exists .... that's what opening doors and having differential temperatures does!

HTH
Z

Absolutely - to control indoor humidity you need to ventilate and at some point you will need to heat the makeup air. For me I designed my own inline fan and a high efficiency filter box, the thing is huge to get more surface area. I even added a hydronic heating coil plumbed into the central heating system to pre heat the incoming air with frost protection on the pump etc.

daveyjp

Totally unscientific results.

November 2018. Heating on an hour in a morning to 16 degrees and from 4-9 pm set at 20. Gas used 1003 kWh

December 2018. House occupied 24/7 and heating set to 20-21 degrees for 12-14 hours.

Gas used 1654kWh

That burst from cold to 20 degrees at 4pm in November was cheap against maintaining 20 degrees all day.

richardc1983

I bet if your comfort temp was 18c you would save money on all the time as the building fabric would be warm at 18c you wouldn't need to heat to 20c. I can set mine at 19c if on 24/7 but needs to be at 22c if off on timed periods as the air temp heats quicker than the fabric and contents of the house.

Plus your best off having it done on the same outdoor temps.. November very mild, December we had some cold snaps so just try two 24 hours periods over two days in the same weather.

cairndog

We have a Honeywell DT92E wireless room thermostat which can be taken into any room we are in.


We also have a large Log Burner in the same room as the unvalved radiator. When the log burner is lit all the radiators in the house go off regardless of their radiator valve set temperature.


However I have noticed that if I take the Wireless thermo into the sitting room we wish to heat then the upstairs radiators all come on.


. The only way to stop this is to move the Wireless thermo back to the room with the lit Logburner (and the unvalved control radiator)


While I do like to heat the upstairs for a while before we go to bed can anyone explain why this happens ?



In plain language, not too technical, please !
Thanks.:question:

Cardew

cairndog wrote: »

We have a Honeywell DT92E wireless room thermostat which can be taken into any room we are in.


We also have a large Log Burner in the same room as the unvalved radiator. When the log burner is lit all the radiators in the house go off regardless of their radiator valve set temperature.


However I have noticed that if I take the Wireless thermo into the sitting room we wish to heat then the upstairs radiators all come on.


. The only way to stop this is to move the Wireless thermo back to the room with the lit Logburner (and the unvalved control radiator)


While I do like to heat the upstairs for a while before we go to bed can anyone explain why this happens ?



In plain language, not too technical, please !
Thanks.:question:

The wireless thermostat switches the heating on and off when the room in which it is placed reaches the temperature set on the thermostat.



For instance if you set the temperature to, say, 20C it will keep the central heating(CH) running until the room reaches approx 20.5C and it will switch off the CH. When the temperature drops to approx 19.5C it will switch on the CH.


Having the thermostat in the room with a large log burner(assuming it is lit!!) will raise the temperature of the room above that set on the thermostat and the CH will be switched off.


If you want other radiators to be heated you have to locate the thermostat in a room where the temperature is below that set on the thermostat. The boiler and pump will then operate and you can control the temperature of other rooms with the TRV

richardc1983

cairndog wrote: »

We have a Honeywell DT92E wireless room thermostat which can be taken into any room we are in.


We also have a large Log Burner in the same room as the unvalved radiator. When the log burner is lit all the radiators in the house go off regardless of their radiator valve set temperature.


However I have noticed that if I take the Wireless thermo into the sitting room we wish to heat then the upstairs radiators all come on.


. The only way to stop this is to move the Wireless thermo back to the room with the lit Logburner (and the unvalved control radiator)


While I do like to heat the upstairs for a while before we go to bed can anyone explain why this happens ?



In plain language, not too technical, please !
Thanks.:question:

So when you want to heat the bedrooms put the thermostat in the room that you want to heat so that it will not be influenced by rooms with other heating in. Basically the log burner is fighting the radiators.

Flt._Lt._Biggles

cairndog wrote: »

...
We also have a large Log Burner in the same room as the unvalved radiator. When the log burner is lit all the radiators in the house go off regardless of their radiator valve set temperature.

... The only way to stop this is to move the Wireless thermo back to the room with the lit Logburner (and the unvalved control radiator)...

Or not light the log burner

Maggie May's going to ban them soon anyway...

zeupater

cairndog wrote: »

We have a Honeywell DT92E wireless room thermostat which can be taken into any room we are in.

We also have a large Log Burner in the same room as the unvalved radiator. When the log burner is lit all the radiators in the house go off regardless of their radiator valve set temperature.

However I have noticed that if I take the Wireless thermo into the sitting room we wish to heat then the upstairs radiators all come on.

. The only way to stop this is to move the Wireless thermo back to the room with the lit Logburner (and the unvalved control radiator)

While I do like to heat the upstairs for a while before we go to bed can anyone explain why this happens ?


In plain language, not too technical, please !
Thanks.:question:

Hi

That's effectively the problem with using portable thermostats to control the heating which isn't fully explained by developers of the (smart?) technologies ....

The central heating system you have installed should have been designed to balance the heat provision for each room to it's particular size and heatloss in order to achieve either a consistent temperature throughout the entire property or a predetermined temperature differential depending on assessed room use which is controlled by a central thermostat ... the (later?) addition of TRVs allows further control by room through restricting flow through individual radiators (& therefore heat output!), totally upsetting the original system balance.

The issue you mention has effectively been around for years in other forms ... in a situation where the central thermostat is in the (say) hallway and the homeowner fits a TRV to a hall radiator (or turns it off, or changes the preset flow balance!) then the thermostat will be affected ... the rest of the house effectively overheats compared to the thermostatic setting ... this is what you're seeing, it's just that you're changing the balance by moving the thermostat into different temperature zones & the heating system hasn't got a clue how to respond other than switching at the preset temperature point.

If you want consistent control you either need to place your mobile thermostat in a consistent location so as to provide control for background heating provision when log burners or gas fires etc are used as primary/secondary heat sources ... or alternatively use a fixed programmable thermostat and use a simple portable thermostatic display (/analogue thermometer!) to provide the information you need ...

I can see it's 21.0C where I'm sitting at the moment, but the GCH thermostat, which is set lower!) is in the hall! ...

HTH
Z