We've a ban on oil-fired central heating (nationally, including in rural areas) in new build from 2022 and gas from 2025, most new build already doesn't have either of them as they would not meet Building Energy Regulation (BER) certification for "A rating" anyway.
There's currently no plan to phase out gas or oil in existing homes though, but there are a lot of incentives coming on stream to move to heat pumps and retrofit homes with better insulation. The modern boilers of both type are pretty efficient. Condensing boilers that recover a very high % of heat have been the norm for quite while, so you'll always see a plume of water vapour emanating from those systems as the flue gasses are very cool.
A lot of older homes here absolutely pathetic levels of insulation. The climate was never extreme enough to make them uncomfortable, so a lot of older houses tended to just use 'cavity walls' which are just a layer of block work - an air gap and an outer layer of brick (or blocks and plaster). The space between the two acted as an insulator, but not a particularly efficient one.
They can be easily retrofitted by drilling holes in the exterior and pumping in either foam or beads.
Very old homes are often just a thick layer of stone or brick without any significant insulation layers other than interior plaster.
Attic / roof insulation is also a relatively modern phenomenon - post 1960s anyway. Prior to that it was common that attics were just empty space without any insulation.
Then most older homes also had fireplaces in every room, with huge heat loss through chimneys, whether or not they were in use. Central heating radiators would typically have been retrofitted in the mid-20th century, but often without removing the fireplaces.
Central heating here, installed anytime before the 1980s was typically pressure-jet oil, burning kerosine/gasoil, including in urban areas as there was no natural gas until the 1970s. Fuel oils were generally never used in domestic heating here. Through the late 70s and 80s and into the 90s natural gas replaced those in cities and small towns, but pressure jet oil remained the de facto standard in rural areas, and took a long time to entirely disappear in urban areas too. Generally it's pretty clean burning though and you wouldn't notice any smell or smoke unless someone's drastically screwed up their burner tuning.
I know of several homes here that still have their original fireplaces in all the bedrooms - was common right up to 1920s and 30s construction.
Floors in older homes are typically suspended on joists over a shallow subfloor which is usually cross-ventilated with vents under the house. Concrete ground floors only became more common in the 1980s. Some houses have concrete floors in the kitchen / utility and suspended floors everywhere else.
Wood frame construction here is still not very popular, largely because of the damp climate. There's been a general history of wood rotting quite easily, so the preference is still for masonry construction, although that's slightly changing in recent decades as wood frame technology has improved.
Homes built in the 20th century (right up to the introduction of complex heat recovery ventilation in the 2000s) also tended to have passive ventilators - which are just literally straight through the wall vents in every room with a 5" duct and mesh and louvers on each end. Those are now increasingly replaced with heat-recovery packs.
Trickle vents in windows are also normally installed - they're a slot at the top of each window - with an closable louver/cover. However, it just means your average Irish one is far, far from 'airtight'
Newer buildings also have a lot of radon countermeasures in place - barriers, sumps, gravel barriers, flue stacks from sumps, and so on as many areas here are granite rock and have a risk, particularly where a building might be recirculating a lot of air or not very well ventilated.
So in general, without deep retrofits of insulation a lot of older homes are totally unsuited to heat pump approaches to heating as they're astronomically expensive to run without it. So we'll probably still have gas boilers running for a long time yet.
But we've a LOOONG way to go before we'll get every building in the country up to high efficiency mode.
[this post was last edited: 12/18/2021-20:38]
