Thermal modernization of the building and the heat pump

With an expert eye

Anna Pawłowska-Kawa, specialist in the field of ecological heating devices

Since 2021, Poland has implemented new Technical Conditions WT 2021, which impose stricter standards for newly constructed homes and their heating systems.

WT 2021 introduces two key conditions. Firstly, it mandates a reduction in the heat transfer coefficient U for individual partitions. Secondly, it requires a decrease in the building’s demand for non-renewable primary energy – EP. While WT 2017 set the requirement at 95 kWh/m², WT 2021 lowers it to just 70 kWh/m². In practical terms, this means that houses granted building permits after January 1, 2021 must not only have minimal heat losses but also be equipped with eco-friendly heating systems to meet these standards.

To illustrate, consider a single-family house with a total usable area of 128 m² in Kraków, located in climate zone III with typical external temperature distribution for Poland, and properly oriented towards the cardinal directions with large south-facing windows. WT 2021 significantly reduces the maximum heat transfer coefficient limits for building partitions Umax, as shown in the table below.

Analyzed variants of heating and ventilation systems, taking into account the heat source:

The results of the analysis divided into the previous WT 2017 and WT 2021 requirements are presented in the chart below:

As depicted in the chart above, only two heating systems can effortlessly comply with the new requirements. These are biomass boilers and air heat pumps paired with a photovoltaic installation. This suggests that we need not fret over the environmental impact of new buildings. However, such eco-friendly houses constitute only a small fraction of the total nationwide. The primary concern lies with older houses, which are the primary culprits for low emissions and pose hurdles to enhancing energy efficiency. The most recent data on our buildings’ condition dates back to 2017 and is detailed in the “Energy efficiency in Poland – review 2017” study.

Back then, a staggering 40% of houses lacked thermal insulation, with only 13% featuring insulation thicker than 10 cm. Such inadequate insulation translates to exorbitant heating costs and heightened emissions of harmful substances from their chimneys. Typically, there’s a direct correlation – the more energy-inefficient the house, the poorer the heating system it houses. While the condition of Polish houses may have improved since 2017, evidenced by the uptick in applications under the Clean Air Program and deductions for thermal modernization, there’s still much ground to cover, especially concerning heating.

What do Poles use to heat themselves?

The Central Emissions Register of Buildings (CEEB) offers the latest insights into heating devices used in Polish households. As of October 23, 2023, there were 17,299,321 distinct heat sources in the country. The majority are attributed to gas heating (27.92%), followed by solid fuel boilers (17.15%) and electric heating (15.05%). Analysis of the solid fuel boiler class reveals that the predominant portion consists of conventional models, often referred to as “Cinderellas” (50.81%). Eco-friendly alternatives and boilers meeting EcoDesign standards make up less than 2% of the total. Among solid fuel boilers, coal-fired ones are most prevalent.

Comparing this substantial number of low-quality devices with the standards outlined in local anti-smog regulations indicates that thermal modernization of Polish homes will pose a significant challenge. All non-compliant devices must be replaced within the specified timelines outlined in the anti-smog regulations of respective voivodeships. Some regions have already implemented bans, such as Świętokrzyskie, Masovian, Małopolskie, Podkarpackie, Silesian, and Łódź provinces. Notably, even class 5 boilers, unless they also meet EcoDesign criteria, will need to be substituted with more environmentally friendly alternatives.

Do heat pumps work in existing homes?

There are several misconceptions surrounding heat pumps, with one common belief being that they are only suitable for new or fully modernized homes. Another misconception is that heat pumps require underfloor heating and are incompatible with traditional radiators. While it’s true that heat pumps operate most efficiently with underfloor heating, they can still effectively provide heating with regular radiators. Both standard heat pumps (with supply temperatures of 55-60°C) and high-temperature models (65-70°C) are available on the market.

Research conducted by Dr. Eng. Marek Miara (PORT PC) at the Fraunhofer ISE Institute in Germany has demonstrated that even in buildings with limited thermal modernization and conventional radiators, heat pumps can achieve the necessary supply temperature of 55°C, ensuring thermal comfort for occupants. This research, based on a monitoring project of heat pumps in existing single-family homes, has provided valuable insights and serves as a reference for leveraging heat pumps in the energy transition towards climate neutrality. Similar monitoring programs conducted in Switzerland have also shown that heat pumps can effectively operate in older homes without underfloor heating, achieving the required supply temperature of 55°C.

Thermal modernization – requirement or recommendation?

It’s always advisable to reduce a building’s energy demand before considering changing the heat source. Lowering the heat demand not only reduces bills but also cuts investment costs by requiring a smaller capacity device. However, complete thermal modernization may not always be feasible due to economic or technical constraints. In such cases, investing in a heat pump may still be beneficial, especially if the existing heat source needs replacement and minor thermal improvements can be made, such as upgrading windows or replacing some radiators with low-temperature ones.

Nevertheless, installing a heat pump in a poorly insulated house with leaky windows or without other energy-saving measures like a photovoltaic installation may not be cost-effective. In such situations, the operating costs of the heat pump could outweigh the benefits. Therefore, a comprehensive energy audit should always precede any decision to install a heat pump. This audit evaluates the current state of the house and estimates how its heat demand will change after any modernization efforts. This approach helps avoid oversizing the heat pump unit and ensures the investment’s viability.

Heat pump as a second heating device?

The discussion on thermal modernization often focuses on replacing non-ecological heating devices like Cinderella boilers. However, homeowners with gas or solid fuel boilers may also consider installing a heat pump, even if their current heating system meets local regulations. Having an additional heat source provides increased comfort and energy security.

Optimizing heating costs involves adapting the heating method and hot water preparation to current fuel or electricity prices. With a backup heat source, homeowners can choose a heat pump with a higher bivalence point, such as -5℃, allowing them to purchase a cheaper unit with lower power. When temperatures drop below the bivalent point, a gas or pellet boiler can effectively heat the house.

What about multi-family buildings?

A significant challenge for achieving energy transformation lies within the multi-family housing sector, despite being a minority in total buildings. In 2021, out of 6.9 million buildings with apartments, 6.3 million were single-family, leaving only 558.4 thousand as multi-apartment buildings. However, these multi-family buildings house approximately 60% of residential premises, making their transition to ecological heating devices crucial for meeting climate goals.

Heat pumps are a potential solution for multi-family buildings, but several conditions must be met. Firstly, they must be high-temperature units to address the increased heat losses in larger buildings, necessitating high-power units or cascade systems composed of multiple units. The sequencing of works is also more complex compared to single-family homes, where reducing heat losses should precede system sizing to avoid oversizing. Precise planning and calculation of energy demand are essential, allowing for the selection of devices tailored to the target demand.

The challenges and solutions regarding heat pumps in multi-family buildings have been extensively studied as part of the “Annex 50 – Heat Pumps in Multi-family Buildings” project supervised by the International Energy Agency (IEA). More information on this project can be found at: [link].

Funding programs

Thermal modernization programs play a vital role in driving our energy transformation, operating at both local and national levels. The Clean Air Programme, with its latest version Clean Air 3.0, places significant emphasis on comprehensive modernization coupled with the installation of photovoltaic micro-installations. Under this program, single-family homes can receive substantial subsidies of up to PLN 135,000. However, support for multi-family buildings was lacking until the introduction of the Warm Apartment Program, which recently launched its second recruitment phase in September.

The Warm Apartment Program extends its support not only to owners of residential premises but also to tenants in municipal buildings and housing communities consisting of 3 to 7 premises. The program offers co-financing of up to 90% of the investment, capped at PLN 41,000 per premises, with higher amounts available in heavily polluted areas, reaching almost PLN 44,000.

Summary

Increasing the adoption of heat pumps in the modernization of Polish homes is essential to meet our climate objectives. The presence of outdated and environmentally unfriendly heating systems in existing buildings contributes significantly to low emissions. Their modernization will be pivotal in enhancing air quality and advancing our energy transition. Heat pumps emerge as the optimal choice, particularly in areas without access to natural gas. While gas boilers may seem more cost-effective initially, it’s crucial to note that gas usage will face restrictions in the future. The European Commission plans to ban gas boilers in new homes by 2030 and potentially in existing ones later on.

Heat pumps, especially those using natural refrigerants, offer a safer and more future-proof solution. Investing in them now can yield long-term benefits, particularly for those generating excess energy from photovoltaic panels. Leveraging energy storage alongside heat pumps can pave the way to nearly complete energy independence, not to mention the significant environmental benefits they offer.

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