ᐅ High Utility Costs in Older Homes – Despite Renovations

Good day,

I registered in this forum hoping to receive good advice. 🙂

Two years ago, we renovated our 40-year-old bungalow. The bungalow has a footprint of 170 m² (1830 ft²) and is fully basemented. We only use the ground floor as living space. Above the ground floor, there is also a concrete ceiling. The exterior wall consists of facing brick, a small, uninsulated and empty cavity, and 40 cm (16 inches) of calcium silicate blocks. So, the exterior walls are not insulated.

During the renovation two years ago, the following was updated:
- New PVC windows (many sliding doors and panoramic windows) with triple glazing, brought up to modern standards
- Ceiling between the ground floor and the attic insulated with 5 cm (2 inches) of polystyrene boards (which were always there) plus an additional 30 cm (12 inches) of mineral wool. A new pitched roof was also installed for 40,000€. Since we do not use the attic, only the ceiling between the floors was insulated with mineral wool. The roof was professionally covered (there is a membrane between the tiles and the roof structure).
- Completely new heating pipes, wall radiators, and underfloor heating. The heating pipes were laid and insulated beneath the basement ceiling. The 18-year-old oil boiler from Buderus (according to the installer and chimney sweep, it has excellent emission values) was kept.

Exactly one year ago, we filled the first oil tank (5000 liters) and now I have measured the oil level. The consumption in one year (3-person household) is 3700 liters. We have large rooms to heat. The living room, dining room, and kitchen are completely open (70 m² / 750 ft²), and the heating in these rooms will now run continuously whenever we are at home. Also, three people shower daily, and in winter, underfloor heating runs in both bathrooms and the kitchen.

The house stays pleasantly cool in summer, probably due to the solid construction (reinforced concrete and calcium silicate blocks). In winter, however, it is also quite cool. We are now unsure whether we made the right decision to renovate the house. Insulating the exterior walls is an option, but it must be extremely costly.

I am a complete novice in this regard and hope for tips and advice from you! Many thanks!

Hello,

padersee13 schrieb:
Two years ago, we renovated our 40-year-old bungalow.

Who provided advice for this?

padersee13 schrieb:
...The 18-year-old oil heating system from Buderus (according to the installer and chimney sweep, excellent emission values) was kept.

This is not an energy assessment in a comprehensive context!

padersee13 schrieb:
...The consumption in one year (3-person household) amounts to 3700 liters.

That is quite substantial!

padersee13 schrieb:
...Insulating the exterior walls is an option, but probably extremely costly.

That is likely not so simple, considering a brick veneer.

padersee13 schrieb:
...I am hoping for tips and advice from you! Thank you very much!

First, the consumption should be attributed to the respective causes before taking further measures. This includes determining the actual demand (capacity, energy) for heating and hot water. It may already be possible to reduce consumption significantly through system optimization, especially if radiators are used as heat emitters.

Best regards

So, I can’t avoid getting an energy consultation. I am not able to provide data on the actual demand for power and energy. I can only measure the oil consumption.
Considering the size of the house and the long hot water pipes that run everywhere (20m (65 feet) to each side of the house), I can only conclude that an oil heating system is simply no longer up to date. Furthermore, I am very concerned about the oil tank because I fear it might eventually develop a leak, which would certainly become very expensive. However, the question remains whether maintenance is worth it. I have decided that if there is major damage, I will immediately invest in a modern heating system, even if it is expensive.

The only real alternatives left to me are basically a new heating system and insulating the exterior walls. Otherwise, everything is already new and insulated.
Also, we do not have municipal water but use our own water supply. Therefore, I cannot provide any data on water consumption, if that is required.

Best regards

Yes, get a new heating system! A layer of insulation between the inner and outer masonry would make sense, as it also provides air insulation.

padersee13 schrieb:
So, I can’t avoid getting an energy consultation.

Not just a consultation => a calculation! The term energy consultant isn’t legally protected; even a building material supplier can use it. I doubt their expertise in technical systems, though.

padersee13 schrieb:
...Because I have decided that if there is major damage, a modern heating system will be installed immediately, even if it’s expensive.

Simply replacing the heat generator often only helps to a limited extent.

Best regards.

Hello,

padersee13 schrieb:
So I can’t avoid getting an energy consultation.

THIS is the wrong mindset! It should be important for you to clarify this topic with an energy consultant. What happens if you don’t, you are currently experiencing firsthand => your problem with high energy costs remains unsolved despite considerable investment.

padersee13 schrieb:

Furthermore, I am very concerned about the oil tank because I fear it will eventually leak, and that would probably become very expensive. However, the question is whether maintenance is worthwhile. I have decided that in case of a major damage, I will immediately install a modern heating system, even if it is costly.

Sealing the oil tank in the worst case is not a big issue for a professional; maintenance of technical systems is always worthwhile by the way!

padersee13 schrieb:

The only alternatives left for me are basically a new heating system and insulating the exterior facade. Otherwise, everything is really new and also insulated.

There is an option to insulate the masonry facade afterwards by injecting insulation material into the cavity. However, it seems more sensible to first invest in an energy consultant; perhaps the oil heating system is the cause, or something else you haven’t considered so far... By the way, the consultant’s fees may be tax-deductible within your tax return 😉

Best regards