When are you putting the heating on this year and what temperature and general heating advice

Grotdog

This is a tricky topic - but something I've been very involved with over the years - we run a Chartered Survey company, and I've written the book on dampness in homes - and the effect that temperature has on the building fabric. I'm sure Martin won't mind me mentioning the name of the book - its out on the 17th Sept, and pre-orders are being taken - called The Warm Dry Home and available on our website - just look for the Heritage House website.. (I'm not sure about the admin rules for posting links) So, back to the topic.

A warm house is a dry one. For a house to be dry, it needs to be warm enough that condensation doesn't form within the building fabric. That means the walls and structure have to be kept above the Dew Point - the temperature at which condensation occurs. Its not something that just forms on surfaces - it forms within the walls, which is what that old fraud of rising damp is about - moisture condensing in brickwork or stone. Where does the moisture come from? Mostly we humans - living, breathing, cooking, showering. It has to go somewhere, and most houses are NOT well enough ventilated - so moisture is able to settle within the fabric - it passes through it as a gas, but if that gas is cooled down below Dew Point, it condenses, and is held in the walls and fabric as water.

 A damp wall transmits heat much quicker than a dry wall, so house gets colder and damper. How do we stop this happening?

We make sure the building stays above a critical temperature - we have a guideline of 15 degrees C., at an RH of 50% - and total moisture content of 7 grams water per cubic metre of air. That's about a teaspoon. Given those parameters, the Dew Point is about 4 degrees C. So you wont get damp, and the house stays dry.

So - how does this relate to the OP? When to turn heating on? You turn it on in such a way that you don't allow the FABRIC of the building to drop below 15 degrees C. You keep it on - constant low temperature heating is cheap to run, and ensures you keep a DRY house, so long as it is well ventilated. I can't emphasise enough that for all this to work you need to ventilate - humidity controlled extraction in kitchens and bathrooms is a must.

So when night time temps start to dip below 15 degrees, you need to get the heating just ticking over, to maintain temps at the right level.  Its not about when, so much as 'what are the temperatures'.. In ALL rooms as well ! Don't leave some rooms with heating off - they'll just get mouldy and manky.

Make sure you also check the building - guttering and downpipes work, drains are clear, there are no cracks allowing water into the ground and soaking the soil at low level - ground levels externally are 150mm below internal floor levels.

All of this promotes dry walls, and thus best chance of maintaining a warm home - which wont lose heat nearly as quickly, and cost less to heat. Remember - it costs a lot more to heat damp air than dry air. 

Ally_E.

Grotdog said:

This is a tricky topic - but something I've been very involved with over the years - we run a Chartered Survey company, and I've written the book on dampness in homes - and the effect that temperature has on the building fabric. I'm sure Martin won't mind me mentioning the name of the book - its out on the 17th Sept, and pre-orders are being taken - called The Warm Dry Home and available on our website - just look for the Heritage House website.. (I'm not sure about the admin rules for posting links) So, back to the topic.

A warm house is a dry one. For a house to be dry, it needs to be warm enough that condensation doesn't form within the building fabric. That means the walls and structure have to be kept above the Dew Point - the temperature at which condensation occurs. Its not something that just forms on surfaces - it forms within the walls, which is what that old fraud of rising damp is about - moisture condensing in brickwork or stone. Where does the moisture come from? Mostly we humans - living, breathing, cooking, showering. It has to go somewhere, and most houses are NOT well enough ventilated - so moisture is able to settle within the fabric - it passes through it as a gas, but if that gas is cooled down below Dew Point, it condenses, and is held in the walls and fabric as water.

 A damp wall transmits heat much quicker than a dry wall, so house gets colder and damper. How do we stop this happening?

We make sure the building stays above a critical temperature - we have a guideline of 15 degrees C., at an RH of 50% - and total moisture content of 7 grams water per cubic metre of air. That's about a teaspoon. Given those parameters, the Dew Point is about 4 degrees C. So you wont get damp, and the house stays dry.

So - how does this relate to the OP? When to turn heating on? You turn it on in such a way that you don't allow the FABRIC of the building to drop below 15 degrees C. You keep it on - constant low temperature heating is cheap to run, and ensures you keep a DRY house, so long as it is well ventilated. I can't emphasise enough that for all this to work you need to ventilate - humidity controlled extraction in kitchens and bathrooms is a must.

So when night time temps start to dip below 15 degrees, you need to get the heating just ticking over, to maintain temps at the right level.  Its not about when, so much as 'what are the temperatures'.. In ALL rooms as well ! Don't leave some rooms with heating off - they'll just get mouldy and manky.

Make sure you also check the building - guttering and downpipes work, drains are clear, there are no cracks allowing water into the ground and soaking the soil at low level - ground levels externally are 150mm below internal floor levels.

All of this promotes dry walls, and thus best chance of maintaining a warm home - which wont lose heat nearly as quickly, and cost less to heat. Remember - it costs a lot more to heat damp air than dry air. 

Hi Pete. I wanted to say I'm a fan, thank you for helping me understand our period home and how important breathability is. I watched all your YouTube videos and recommend them whenever the topic of breathable homes comes up. 

Novice_investor101

I always used to feel cold even though the thermometer said it was 21c in my lounge & kitchen. Although never upstairs even though that was the same temp. 

That was solved when I bought a dehumidifier & ran it downstairs for a week. The amount of moisture that it sucked up was incredible! & it was coming out of the walls because I could smell it, & 2 small damp patches on internal walls dried up. Prior to that I’d never have thought of my house as damp because there’s no mould or signs of damp. I have the dehumidifier running all the time now, keeping the downstairs at a max 60% in the summer & 50% in the winter. I’ve never been cold with the heating on since. 

Upstairs I always have the bedroom & bathroom windows cracked open, that was probably the difference in humidity. 

Zaul22

Normally I would only turn it on if it gets below 10C. If the bill freeze was not happening I would probably have to lower that to 8 or maybe even 5. 

I don't understand anyone that sets their house temperature higher than 20C. 20+ degrees is shorts and T-shirts level hot.  

lordsarnoc

Grotdog said:

A warm house is a dry one. For a house to be dry, it needs to be warm enough that condensation doesn't form within the building fabric. That means the walls and structure have to be kept above the Dew Point - the temperature at which condensation occurs. Its not something that just forms on surfaces - it forms within the walls, which is what that old fraud of rising damp is about - moisture condensing in brickwork or stone. Where does the moisture come from? Mostly we humans - living, breathing, cooking, showering. It has to go somewhere, and most houses are NOT well enough ventilated - so moisture is able to settle within the fabric - it passes through it as a gas, but if that gas is cooled down below Dew Point, it condenses, and is held in the walls and fabric as water.

So when night time temps start to dip below 15 degrees, you need to get the heating just ticking over, to maintain temps at the right level.  Its not about when, so much as 'what are the temperatures'.. In ALL rooms as well ! Don't leave some rooms with heating off - they'll just get mouldy and manky.

I don't post here often, but as I live in a 2 bed Victorian terrace, I discovered the hard way that you have to heat the house to a minimum level. Thought I'd hold off turning the heating on until as late as possible (November). Plenty of condensation / mould on the front (north-east facing) wall. Since then I've discovered that 16.5 degrees on the Hive thermostat on the landing, unless we're away where I can afford to let it drop further (15 seems about right) is the absolute minimum temperature possible without encouraging the condensation to come back. 

So I definitely think you're doing something important here!

Auti

Novice_investor101 said:

I always used to feel cold even though the thermometer said it was 21c in my lounge & kitchen. Although never upstairs even though that was the same temp. 

That was solved when I bought a dehumidifier & ran it downstairs for a week. The amount of moisture that it sucked up was incredible! & it was coming out of the walls because I could smell it, & 2 small damp patches on internal walls dried up. Prior to that I’d never have thought of my house as damp because there’s no mould or signs of damp. I have the dehumidifier running all the time now, keeping the downstairs at a max 60% in the summer & 50% in the winter. I’ve never been cold with the heating on since. 

Upstairs I always have the bedroom & bathroom windows cracked open, that was probably the difference in humidity. 

Hi, how expensive is your dehumidifier to run. I live near the sea and even with windows wide open humidity was at 70% and temp was 24 degrees C inside the house. I don‘t know if it is because I am near the sea even my humidistat (set at 50) bathroom fan came on randomly because of the air humidity (no one had used bathroom). I am concerned about electricity costs and damp and all of it as it seems you are stuffed one way or the other!

savingdiva

In a 70's house, so won't be putting heating on until absolutely necessary and on just enough to remove chill. Have got door poles on front, back and living room, with  curtains. Have knitted legwarmers, fingerless gloves and blanket. Fortunately I live by myself so can only use one room most of the day 

Coffeekup

Grotdog said:

This is a tricky topic - but something I've been very involved with over the years - we run a Chartered Survey company, and I've written the book on dampness in homes - and the effect that temperature has on the building fabric. I'm sure Martin won't mind me mentioning the name of the book - its out on the 17th Sept, and pre-orders are being taken - called The Warm Dry Home and available on our website - just look for the Heritage House website.. (I'm not sure about the admin rules for posting links) So, back to the topic.

A warm house is a dry one. For a house to be dry, it needs to be warm enough that condensation doesn't form within the building fabric. That means the walls and structure have to be kept above the Dew Point - the temperature at which condensation occurs. Its not something that just forms on surfaces - it forms within the walls, which is what that old fraud of rising damp is about - moisture condensing in brickwork or stone. Where does the moisture come from? Mostly we humans - living, breathing, cooking, showering. It has to go somewhere, and most houses are NOT well enough ventilated - so moisture is able to settle within the fabric - it passes through it as a gas, but if that gas is cooled down below Dew Point, it condenses, and is held in the walls and fabric as water.

 A damp wall transmits heat much quicker than a dry wall, so house gets colder and damper. How do we stop this happening?

We make sure the building stays above a critical temperature - we have a guideline of 15 degrees C., at an RH of 50% - and total moisture content of 7 grams water per cubic metre of air. That's about a teaspoon. Given those parameters, the Dew Point is about 4 degrees C. So you wont get damp, and the house stays dry.

So - how does this relate to the OP? When to turn heating on? You turn it on in such a way that you don't allow the FABRIC of the building to drop below 15 degrees C. You keep it on - constant low temperature heating is cheap to run, and ensures you keep a DRY house, so long as it is well ventilated. I can't emphasise enough that for all this to work you need to ventilate - humidity controlled extraction in kitchens and bathrooms is a must.

So when night time temps start to dip below 15 degrees, you need to get the heating just ticking over, to maintain temps at the right level.  Its not about when, so much as 'what are the temperatures'.. In ALL rooms as well ! Don't leave some rooms with heating off - they'll just get mouldy and manky.

Make sure you also check the building - guttering and downpipes work, drains are clear, there are no cracks allowing water into the ground and soaking the soil at low level - ground levels externally are 150mm below internal floor levels.

All of this promotes dry walls, and thus best chance of maintaining a warm home - which wont lose heat nearly as quickly, and cost less to heat. Remember - it costs a lot more to heat damp air than dry air. 

Very interesting.... Slightly off topic and strange question... How does this compare with condensation on the outside of window in winter times? Is outside condensation a good thing, sign of damper outside than in?

Chrysalis

Might be getting PCV windows finally, LL sent someone round to clean up the rot and repaint so the property doesnt look unmaintained from the outside, when he started scraping away, the window frame collapsed.  He has gone back to tell them its "beyond repair". Struggle to see how LL wiggles out of spending the money now so should get better heat retention this winter.

sandy700

Zaul22 said:

I don't understand anyone that sets their house temperature higher than 20C. 20+ degrees is shorts and T-shirts level hot.  

Wait until you reach my age (76) and start taking bisoprolol for angina.

I was at the hospital yesterday seeing a heart specialist and he confirmed that feeling cold was one of the side effects of bisoprolol, he said turn the thermostat as high as is comfortable.

I asked him if the NHS would pay the bill.

He just laughed.