ᐅ Passive House as a Logical Choice? Are There Any Counterarguments?

...wrong Mycraft,

this is from the terms and conditions of Program 153 (0.75% interest)

During the initial fixed interest period, you can repay the loan amount in full or in partial amounts starting from 1,000 euros (approximately 1,100 US dollars) without any additional costs.

The conditions at 153 and 124 differ significantly in this regard!!!

Bauexperte schrieb:
If you now consult Google with "Passive House + certified Passive House components," you should be able to explain to me why a 2% additional cost is more realistic than 40%...

Then can you also explain to me how anyone in Freiburg, for example, can still afford to build?

For me, Passive House doesn’t necessarily mean just sticking the certificate from the Passive House Institute on the paperwork. The core requirements are an air change rate below 0.6 and annual heating demand less than 15 kWh/m². For that, certified components aren’t absolutely necessary; what matters more are skilled tradespeople working carefully.

The question of additional costs naturally depends on what you compare it to. If you compare it to a cheap builder who barely complies with the energy saving regulations on paper, then 40% might still be realistic. But compared to what most people here seem to build, in my opinion, that’s clearly exaggerated.

Almost everyone already has controlled mechanical ventilation, you can save on expensive underfloor heating in a Passive House, and triple glazing is also standard. (Not to mention the fireplaces some install to save on heating costs.) So where are the big extra costs supposed to come from?

Just as a thought: Yes, many build with triple glazing, mechanical ventilation with heat recovery, and a heat pump, but even with the already significant financial investment, they only reach about KfW 70 level. For a passive house, you really have to push yourself further, including financially. If it were that easy and affordable, wouldn’t everyone else (including us) have already upgraded to a passive house?

Good evening,

After a long day, I’m still at the desk a little; preparing for tomorrow’s trade fair.

nathi schrieb:

If you then explain to me how anyone can still afford to build in Freiburg, for example?

You’ve written this twice now… and since I couldn’t know—I live and work in NRW—I took a look at Freiburg’s city website.

Freiburg Efficiency House Standard 55 (new residential buildings)

This standard is set in urban development contracts for residential plots in new zoning plans (public display resolutions after September 30, 2011) and in purchase agreements for municipal residential plots entered into after September 30, 2011.

The previously valid Freiburg efficiency house standards 40 and 60 are combined into the new Freiburg Efficiency House Standard 55. The Fr-EH 55 corresponds to a KfW Efficiency House 55 (Energy Saving Ordinance 2014) with a verified airtightness of n50 ≤ 0.60/h and a controlled ventilation system with heat recovery (efficiency > 75%). The primary energy demand of 55% and the specific transmission heat loss of 70% of the respective requirement values according to the Energy Saving Ordinance 2014 must not be exceeded.

I find no indication here that only passive houses are approved; on the contrary, it reads as if all efficiency levels starting from KfW 55 receive approval, provided that the plot is allocated by the municipality. These days, this is an affordable investment with additional costs around TEUR 8.5 (8500 euros).

nathi schrieb:

To me, passive house doesn’t necessarily mean merely sticking the certificate from the Passive House Institute on it. The actual requirements are an air change rate < 0.6 and annual heating energy < 15 kWh/m². For that, certified components are not necessarily required; more important are carefully working craftsmen.

The term “passive house” is not legally protected, nor are the components explicitly defined anywhere. **Certification as a “quality-controlled passive house” (with the PHI label) is an offer from the Passive House Institute (PHI). No one is “required” to certify their passive house. However, since these requirements are truly new for many planners, builders, and contractors, certification is a good way to ensure these criteria are met. It also strengthens trust between provider and buyer. Moreover, good quality assurance during the planning process often saves a lot of money. The PHI stands behind this certification with its reputation—the PHI label is therefore a protected trademark. Only certification bodies recognized by the PHI are authorized to use this label.

nathi schrieb:

Where are the big extra costs supposed to come from?

***A residential building qualifies as a passive house if it meets the following three requirements:

1. A comfortable indoor climate can be maintained without a separate heating system or air conditioning: the annual heating demand calculated using the Passive House Planning Package (PHPP) must not exceed 15 kWh/(m²a).

2. Comfort criteria must be met in every living space during winter and summer. This generally results in the following requirements:

• U-values of opaque exterior components must be below 0.15 W/(m²K).
• U-values of windows and other translucent components must be below 0.8 W/(m²K).
• Translucent surfaces facing west or east (±50°) as well as translucent surfaces with inclinations less than 75° relative to the horizontal must not exceed 15% of the usable area behind them or must have temporary solar shading with a reduction factor of at least 75%. For south-facing windows, the limit is 25% of the usable area behind them.
• Supply air temperature at room air outlets must not drop below 17°C (63°F). Even airflow through and within all rooms must be ensured (ventilation efficiency). Ventilation must primarily target air hygiene (DIN 1946). Noise from the ventilation system must be very low (< 25 dBA).
• The building must have at least one operable outdoor air opening in every living space, allowing airflow through the dwelling (free summer cooling).

3. The specific primary energy demand for all household applications (heating, hot water, and household electricity) must not exceed 120 kWh/(m²a). The calculation is based on PHPP.

The reference building values according to the Energy Saving Ordinance are:

Roof: UREF 0.20 W/(m²K)
Walls: UREF 0.28 W/(m²K)
Thermal bridges: UREF 0.05 W/(m²K)
Ground slab: UREF 0.35 W/(m²K)
Windows: UREF 1.3 W/(m²K)
Heating: Gas condensing boiler + solar water heating
Primary energy demand: QREF 83.41 kWh/(m²a)

***The following principles apply to passive house construction:

Thermal insulation
All opaque building envelope components are insulated to a level achieving a maximum heat transfer coefficient (U-value) of 0.15 W/(m²K), meaning a maximum heat loss of 0.15 watts per square meter of exterior surface per degree of temperature difference.

Passive house windows
Windows (glazing including frames) should not exceed a U-value of 0.80 W/(m²K) with g-values around 50% (g-value = total solar energy transmittance, the share of solar energy available to the room).

Heat Recovery Ventilation
Comfort ventilation with highly efficient heat recovery primarily ensures good indoor air quality and secondly saves energy. At least 75% of the heat from exhaust air is recovered via a heat exchanger and transferred to the incoming fresh air.

Building airtightness
Leakage through uncontrolled gaps must be below 0.6 air changes per hour at 50 pascals pressure difference during pressure testing.

Thermal bridge-free construction
All edges, corners, connections, and penetrations must be carefully planned and executed to avoid thermal bridges. Any unavoidable thermal bridges should be minimized as much as possible.

**Source: IG Passive House
***Source: Passive House Institute

Deviating requirements for masonry, ground slab, roof, insulation, windows, ventilation, and heating load model according to PHPP compared to the reference building based on the Energy Saving Ordinance 2014 quickly lead to additional costs in the range of 40%. These costs are likely to decrease in the coming years; however, potential builders should not lose sight of this extra investment at the moment.

I always have to smile: in the heating load calculation of a passive house, the body heat of future occupants is factored in. There is a passive house in Lehrte as a show house where the sales staff sometimes put a small heater on during certain seasons.

Best regards,
Bauexperte

Sorry, your post is a bit hard to read. Just a quick note about Freiburg:

Bauexperte schrieb:
proven airtightness n50 ≤ 0.60/h

This certainly wouldn’t allow standard KfW 55 houses, since there the requirement is only n50 ≤ 1.5/h.
So, at least very careful workmanship is necessary. And that brings us back to what I wrote, right?
You are also arriving at a figure of around 2%.

PHI doesn’t matter to me in this case, as I said, PHPP is what counts, for example to qualify for the KfW subsidy.