Old houses versus new building

[Mick Dempsey]

I like old houses, energy wise we heat ours with wood. Insulation is all about windows and doors.

 

Admiitedly it is a small house, and the climate here is warmer than the UK. 

[Chris at eden]

6 minutes ago, Mick Dempsey said:

I like old houses

What he said.  The only way I would buy a new house is if it was a self build so its not rammed on top of the next one on a housing estate and you can inject a bit of character / style into it.   

[Big J]

5 minutes ago, Mick Dempsey said:

I like old houses, energy wise we heat ours with wood. Insulation is all about windows and doors.

 

Admiitedly it is a small house, and the climate here is warmer than the UK. 

Not entirely. 

 

Equally important are thermal bridges, a continuous insulation layer, thermal mass, air tightness (which does come into windows and doors, but a badly constructed wall will leak air too), moisture permeability of the wall, and the condensation point within it, as well as the moisture gradient within the wall. 

 

One of the main advantages of a well insulated house (from my perspective) is the ability to keep it cool in summer. You can usually heat a house to the point of being comfortable in winter, but a badly insulated building is difficult to keep cool in summer.

[Mick Dempsey]

Well it’s all about windows and doors here, once o got those sorted it’s toasty in winter.

 

The walls are thick (90cm) stone, not a problem in summer.

[Big J]

1 minute ago, Mick Dempsey said:

Well it’s all about windows and doors here, once o got those sorted it’s toasty in winter.

 

The walls are thick (90cm) stone, not a problem in summer.

My Dad's house is something similar, but it does get warm in summer. He's about an hour south of Poitiers. 

 

France has an enviable winter. Really quite short, but cold enough to be a considered a proper winter

[Mick Dempsey]

Truth be told at 35c the upstairs does warm up un peu trop, but in a new, ultra insulated house without air con it would be a whole lot worse.

[Woodworks]

44 minutes ago, Big J said:

 

 

What it needed was the roof completely rebuilding and completely cladding and externally insulating. And I reckon that would have cost as much as knocking it down and rebuilding.

 

Not pretending it's cheap but it is no way as expensive as a rebuild. I will see if I can dig out some numbers

[Big J]

3 minutes ago, Mick Dempsey said:

Truth be told at 35c the upstairs does warm up un peu trop, but in a new, ultra insulated house without air con it would be a whole lot worse.

I've discussed this statement with my wife, and the issue is that the bulk of modern houses are so badly built that in part, what you say is true. However, it is possible to build houses far better than anything that has historically been built and in terms of keeping cool in summer in warmer climates, it comes down to a few things:

 

• Thermal mass. This is where older houses often score well. They have a longer lag time between the start of higher external temperatures and the house heating up. This is easily achievable with new builds, and requires a insulative envelope around a body of thermal mass, such as unfired clay bricks, or concrete floors. 
• Solar shading. Most new builds are built without any consideration to the movement of the sun, the angle in the sky and the heating effect it will have in summer. Solar shading means minimal direct sunlight in the house during high summer (when you want to avoid that thermal gain) but that you still get plenty of light in winter when the sun is lower in the sky.
• MVHR - good ventilation, including a heat exchanger will really help. Ventilate the house extensively overnight when temperatures are lower, and less through the day. 

There are lots more points to make, but yes, I agree, a lot of old houses are good at staying cool in summer. Our 1840s house isn't one of them though!

[Mick Dempsey]

Part of the problem upstairs are the velux, which allow sunlight in but not the heat out, if you see what I mean.

[Big J]

2 hours ago, Mick Dempsey said:

Part of the problem upstairs are the velux, which allow sunlight in but not the heat out, if you see what I mean.

Yeah, they are difficult to work with. 

 

Ideally you don't want any windows in the roof itself, rather a good overhang on the eaves and gable ends, and windows contained within the wall.