Hello,
I want to renovate my parents' house, which we will move into in 2 years. Currently, there is an oil heating system installed, which was renewed around 2005. However, the radiators are as old as the house itself (1972). I assume the heating system operates as a high-temperature one.
Questions:
1. How can I determine if the system supports both high- and low-temperature operation?
I would like to have the radiators removed and replaced with underfloor heating.
2. I found some systems where underfloor heating can be retrofitted. Can such a system replace a radiator?
3. There are a few rooms where underfloor heating is not possible. Is it simply possible to replace the old radiators with new low-temperature radiators in these rooms? Of course, this assumes that question 1 can be answered with YES.
I want to renovate my parents' house, which we will move into in 2 years. Currently, there is an oil heating system installed, which was renewed around 2005. However, the radiators are as old as the house itself (1972). I assume the heating system operates as a high-temperature one.
Questions:
1. How can I determine if the system supports both high- and low-temperature operation?
I would like to have the radiators removed and replaced with underfloor heating.
2. I found some systems where underfloor heating can be retrofitted. Can such a system replace a radiator?
3. There are a few rooms where underfloor heating is not possible. Is it simply possible to replace the old radiators with new low-temperature radiators in these rooms? Of course, this assumes that question 1 can be answered with YES.
I should mention that you also plan to do some major remodeling.
The project sounds reasonable so far. For the old radiator recesses, either use the same wall material as the rest of the wall or aerated concrete. Do not use insulation boards or similar materials; instead, fully bond the surface with mortar or construction adhesive without any air gaps.
With a well-insulated roof, new windows, and closed recesses, underfloor heating should also be possible. Probably not with a supply temperature of 28-30°C (82-86°F), but below 40°C (104°F) should be achievable. Depending on the wall structure, even lower temperatures may be possible.
For bricking up, you will need to remove the screed in the radiator niches anyway. This will show you its thickness and what is underneath. I would guess 4-6 cm (1.5-2.5 inches) of screed with 2-4 cm (0.8-1.5 inches) of mineral wool below. Screed thicknesses of 8 cm (3 inches) are rather rare. The screed probably was not fiber-reinforced at that time but instead reinforced with a wire mesh-like grid embedded in it.
Technically, the removal is not difficult: use a proper electric hammer drill (6-9 kg / 13-20 lbs) and get started. If there is wire reinforcement, don’t break everything into small pieces; rather, cut off larger panels and snip the wires with tin snips / diagonal cutters / pliers / cordless angle grinder.
Be sure to wear appropriate respiratory protection when handling old mineral wool. Not the cheap masks from hardware stores, but the high-quality ones from specialist suppliers. You can find the exact specifications online in the processing guidelines for old mineral wool.
Collect and dispose of mineral wool separately (not with general construction waste or mixed debris, but in sealable bags; some landfills only accept mineral wool in big bags).
With two people, you can manage about 100 m² (1,076 sq ft) per day.
For rebuilding with underfloor heating, follow the substrate and available build-up height. There are many options, but the new-build method with insulation + underfloor heating + 5 cm (2 inches) screed cover is probably not the best choice, as it requires a 15 cm (6 inches) build-up height. Otherwise, the insulation underneath will be insufficient.
A thin-layer system with dry screed would be a quick and DIY-friendly solution. My favorite solution is the one by WEDI (also works with other cement-coated XPS boards). Check their site or search online for “underfloor heating with WEDI boards.” According to the manufacturer, this method is only suitable with tile flooring on top, but multilayer glued engineered wood floors should not pose a problem either.
By the way — you should replace the oil heating system, as it has passed its prime. Switching to a modern oil condensing boiler with an exhaust temperature of around 35°C (95°F) can save you about 15% in oil consumption.
The project sounds reasonable so far. For the old radiator recesses, either use the same wall material as the rest of the wall or aerated concrete. Do not use insulation boards or similar materials; instead, fully bond the surface with mortar or construction adhesive without any air gaps.
With a well-insulated roof, new windows, and closed recesses, underfloor heating should also be possible. Probably not with a supply temperature of 28-30°C (82-86°F), but below 40°C (104°F) should be achievable. Depending on the wall structure, even lower temperatures may be possible.
For bricking up, you will need to remove the screed in the radiator niches anyway. This will show you its thickness and what is underneath. I would guess 4-6 cm (1.5-2.5 inches) of screed with 2-4 cm (0.8-1.5 inches) of mineral wool below. Screed thicknesses of 8 cm (3 inches) are rather rare. The screed probably was not fiber-reinforced at that time but instead reinforced with a wire mesh-like grid embedded in it.
Technically, the removal is not difficult: use a proper electric hammer drill (6-9 kg / 13-20 lbs) and get started. If there is wire reinforcement, don’t break everything into small pieces; rather, cut off larger panels and snip the wires with tin snips / diagonal cutters / pliers / cordless angle grinder.
Be sure to wear appropriate respiratory protection when handling old mineral wool. Not the cheap masks from hardware stores, but the high-quality ones from specialist suppliers. You can find the exact specifications online in the processing guidelines for old mineral wool.
Collect and dispose of mineral wool separately (not with general construction waste or mixed debris, but in sealable bags; some landfills only accept mineral wool in big bags).
With two people, you can manage about 100 m² (1,076 sq ft) per day.
For rebuilding with underfloor heating, follow the substrate and available build-up height. There are many options, but the new-build method with insulation + underfloor heating + 5 cm (2 inches) screed cover is probably not the best choice, as it requires a 15 cm (6 inches) build-up height. Otherwise, the insulation underneath will be insufficient.
A thin-layer system with dry screed would be a quick and DIY-friendly solution. My favorite solution is the one by WEDI (also works with other cement-coated XPS boards). Check their site or search online for “underfloor heating with WEDI boards.” According to the manufacturer, this method is only suitable with tile flooring on top, but multilayer glued engineered wood floors should not pose a problem either.
By the way — you should replace the oil heating system, as it has passed its prime. Switching to a modern oil condensing boiler with an exhaust temperature of around 35°C (95°F) can save you about 15% in oil consumption.
Well, if the oil heating system has to be completely removed anyway, then something that doesn't use oil will be installed. I'm still not sure what exactly will be put in there... hmm, a new project... well, I had already planned a new heating system that doesn't require oil, but I was thinking of waiting about 10 more years for that.
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