Insulate background information

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The content on this page is taken from the Insulate webpage.

We have gathered here some relevant information concerning buildings, energy efficiency, indoor environmental quality (IEQ) and health; please see the sub-pages.

Buildings

Building assessment

Building assessments give information about the condition of buildings as well as on the need for and anticipated cost of renovation. Major repairs and renovation foreseen within the next five to ten years as well as need for more in-depth building inspections are typically included in the building assessment report.

Structural engineering experts as well as experts in heating, plumbing, ventilation and electrical installation are needed for performing a completed building assessment. It is usually recommended that first assessment should be performed when the building is about 10 years of age. After that, the assessment should be updated every five to ten years. Energy audits and related assessments can be performed at the same time.

Building assessments are commonly conducted as building walkthroughs utilizing checklists and other non-destructive assessment methods. While some simple measurements can be taken, the assessment is mainly based on a visual evaluation of the building’s condition and of the need for renovation. Building assessments may be further complemented by interviewing or surveying building occupants to collect information and perceptions about the building. There are some common guidelines for ordering, performing, and reporting building assessments, and in some countries, building owners may apply for financial aid to cover the costs related to building assessments.

Building inspections

If persons conducting building assessments deem it difficult to assess the condition of some parts of the building, they will propose a more detailed inspection. On one hand, building inspections give more precise and detailed information about the condition of critical parts of the building. On the other hand, they give information that will help in planning renovations and in choosing appropriate renovation methods. Typically, building inspections can focus on:

  • Structures or structural components, such as outer walls, balconies, rooms with a floor gully, roofs
  • Plumbing system
  • Electrical systems
  • Heating systems
  • Ventilation systems
  • Indoor environmental quality (IEQ)

Professional education and experience is required for performing these inspections. The inspector should also have proper tools and equipment for taking and analyzing samples.

The methods and procedures of the inspection vary depending on the inspection target. There are several methods and combinations of methods which inspectors can use in their work:

  • Studying design plans and other documents
  • Visually-based inspection
  • Structural openings and other destructive methods
  • In situ measurements and tests
  • Illustrations and viewing of structures and piping
  • Taking samples and analyzing them at a laboratory.

In the following, some structural measurements are described which can be included in building inspections that could also be related to IEQ.

Surface temperatures

Measuring surface temperatures of the outer walls helps tracking spots with poor thermal insulation, heat/cold bridges, and air leakage. Surface temperatures can be measured using thermographic camera or surface temperature meters. Surface temperature is usually presented as a thermal index (TI), which takes into account outdoor and average indoor temperature at the measurement point. According to the Finnish Housing and Health Guide (Asumisterveysohje 2003), a good level is TI ≥ 65 and an adequate level is TI ≥ 61.

Airtightness

Airtightness of the building envelope is usually determined by so-called blower door tests. The special equipment (blower door) is installed on one door and all other openings (doors, windows, chimneys, ventilation vents) are sealed. The equipment creates 50 Pascal under or over pressure into the whole building and measures leaking air. It also calculates the airtightness value, n50 or air leakage value q50. If some other value than q50=4 m3/h m2 is used for calculating the E-value of the building, the airtightness of the building should be measured. Measuring the airtightness of an entire apartment building is quite difficult and laborious work, since all openings in all the apartments should be sealed. It is also possible to measure airtightness of one apartment, but the results will not be very reliable because of some air leakages through the walls between apartments.

Insulate airtightness.jpg

Air change rate

Measuring air change rate is a basic part of an inspection of the ventilation systems. The inspection includes visual inspection of the condition and cleanness of the air channels, vents, and air supply units. If the building is equipped with mechanical ventilation, the air exchange rate could be assessed by measuring air flows from the exhaust air vents. It is quite difficult to assess the air change rate if the building has natural ventilation. In such cases, air change rate can be assessed by using a so-called tracer gas method. It is commonly agreed upon that the air change of an apartment should be at least 0.5 m3/h in all the rooms (air change rate 0.5 l/h).

Pressure difference

Balancing the ventilation is critical for managing the pressure difference between outdoor and indoor air. Also the temperature differences between the indoor and outdoor as well as the outdoor conditions, such as wind, affect the pressure difference.

Insulate pressure difference.jpg

High over pressure between the outdoor and the indoor may lead to moist indoor air transferring into the structures and resulting in condensation, while high under pressure may lead to all the impurities of the structures and surrounding environment (e.g. radon from the soil underneath the building) being sucked into the indoor air. Table 2 shows the acceptable pressure differences in the different types of ventilation systems, according to the Finnish guidelines. [1]

Ventilation system Pressure difference Notes
Natural 0...-5 Pa against outdoor

0 Pa against staircase

Pressure differences vary a lot enclosed to weather
Mechanical exhaust -5...-20 Pa against outdoor

0...-5 Pa against staircase

Pressure differences vary a lot enclosed to weather
Mechanical inlet and exhaust 0...-2 Pa against outdoor

0 Pa against staircase

Pressure differences vary a lot enclosed to weather

Energy efficiency

Energy efficiency and energy consumption

Energy efficiency (EE) is a commonly agreed method of presenting energy consumption in a comparative form. It is based on the so-called standard use of the building as well as on certain components, such as ventilation, warm water, lightning and indoor temperature. Energy consumption is also calculated using commonly agreed outdoor climate values, for instance the climate zone 1 (Helsinki-Vantaa) in Finland. The energy efficiency value (E-value) is based on the calculated total energy consumption multiplied with the energy source coefficient. Rules for calculating E-value vary across Europe. In Finland, building energy efficiency used to be presented with the so-called ET value before adopting the EE value. The two values are not comparable.

Measured energy consumption is another way of presenting the energy consumption or energy efficiency of a building.

Factors affecting EE

Energy consumption is in principle the energy used for heating, minus the internal (people, devises) and external (solar) heat gains.

There are several factors affecting the energy efficiency of buildings:

  • Structures facing outdoor (walls, roofs, floors, windows, doors); primary depending on thermal resistance of structures (U-values)
  • Airtightness of the building envelope; low airtightness increases air leakages and energy losses
  • Ventilation; sufficient ventilation to maintain good indoor air quality (IAQ), but not too efficient to cause heat loss (heat recovery system in mechanical ventilation systems minimizes heat loss)
  • Energy needed for warming up water
  • Energy needed for lighting
  • Energy needed for electric devices inside the building
  • Solar radiation through windows depending on various factors (orientation, shading, type of windows, etc.)
  • Heat gain from people, lightning and electric devises inside the building (warm up the indoor temperature and, therefore, reduce the energy needed for heating)
  • Efficiency of the technical systems (heat loss in the heating systems etc.).

Table 1 shows how the acceptable U-values for building components have changed in Finland during the past decades.

Table 1. Acceptable U-values and other boundary values in the energy consumption calculations.
U-values on building component 1976 1978 1985 2003 2007 2010 2012*
Outer wall 0,4 0,29 0,28 0,25 0,24 0,17 0,17
Roof 0,35 0,23 0,22 0,16 0,15 0,09 0,09
Floor 0,40 0,40 0,36 0,25 0,24 0,17/0,16 0,17/0,16
Window 2,1 2,1 2,1 1,4 1,4 1,0 1,0
Door 0,7 0,7 0,7 1,4 1,4 1,0 1,0
Other boundary values for calculation
n50-value (airtightness) 6 6 6 4 4 2 2
Annual coefficient of efficiency of heat recovery 0 0 0 30% 30% 50% 45%
Compensation possibility in heat flow of envelope 0 0 0 10% 20% 30%
*The total energy consumption will be multiplied with coefficient depended on energy source. The limit values of 2012 are leading average 20% energy demand compared with 2010 values.

Possibilities to improve EE

The Housing Finance and Development Centre of Finland (ARA) has listed 16 actions for improving energy efficiency:

  1. Improving windows by refurbishing
  2. Replacing windows
  3. Improving outer walls by adding thermal insulation, at least 50 mm
  4. Improving outer walls by adding thermal insulation, at least 100 mm
  5. Improving roof by adding thermal insulation, at least 150 mm
  6. Adjusting ventilation (basis adjustment)
  7. Building new heat recovery system into the ventilation system
  8. Joining to district heating or zone heating system
  9. Renewing heat distribution center of real estate
  10. Renewing oil-fired boiler or oil burner
  11. Replacing old room heating or water circulating heating by electricity with new central heating by geothermal heat pump
  12. Supplementing old electricity room heating with air heat pump
  13. Replacing old heating system with new low emission pellet boiler
  14. Installing apartment specific water meters
  15. Adjusting heating grid (basic adjustment)
  16. Supplementing old electricity or oil burner system with solar heating system

Energy audit

An energy audit must be included in all new building permits (as of 2008). The audit includes the source information form, final results of the calculations, regular calculations as well as the energy performance certificate (EPC). The survey for new buildings includes the following parts:

  1. Report that the thermal losses of the building fulfill existing regulations
  2. Calculation of the electric power of ventilation system
  3. Estimation of the heating energy needed in the building
  4. Estimation of the summer indoor temperature (and cooling energy need, if needed)
  5. Estimation of the actual energy consumption of the building
  6. Energy certificate, including the energy class (E-value A….E).

There are limit values for the E-value, based on different type and size of the building. The EPC is a tool for comparing the energy efficiency of the different buildings. The EPC with the E-value is based on properties of the building, not the current use of the building. In old buildings the EPC usually includes also the report of the actual energy consumption, but the energy class is only based on the calculations.

The EPC should be presented when applying for the building permits and when selling or renting the building or the apartment.

IEQ

About IEQ

Indoor environmental quality (IEQ) is influenced by thermal conditions, ventilation, and indoor air pollutants (such as particles, microbes, chemical impurities, and radon), which are also known to have effects on the health and well-being of building occupants. In the following is a summary of IEQ parameters, which could be affected by improved energy efficiency. Checking compliance with the national/EU guidelines (see Table 1) can help the building owners and occupants plan and take actions for healthier indoor environment as a potential co-benefit of the energy retrofit.

Table 1. Guidelines for some IEQ parameters
IEQ parameter WHO guideline EU/National level guidelines U.S. EPA Guideline
Finland Lithuania
Temperature - (18) 21°C 20-14°C -
Relative humidity 20-60% 40-60%
CO2 1200-1500 ppm 1200 ppm 1000 ppm
CO 8,6 ppm (8 h)

25 ppm (1 h)

10 µg/m3 (8 h)

6,9 ppm

3 mg/m3 (24 h)

2.43 ppm (24 h)

9 ppm (8 h)

35 ppm (1 h)

PM10 20 µg/m3 (1 yr)

50 µg/m3 (24 yr)

20 µg/m3 (1 yr)

50 µg/m3 (24 hr)

20 µg/m3 (1 yr)

50 µg/m3 (24 hr)

Revoked (1 yr)

150 µg/m3 (24 yr)

PM2.5 10 µg/m3 (1 yr)

25 µg/m3 (24 yr)

Stage 1: 25 µg/m3 (1 yr)

Stage 2: 20 µg/m3 (1 yr)

40 µg/m3 (24 r)

Stage 1 25 µg/m3 (1 yr)

Stage 2 20 µg/m3 (1 yr)

40 µg/m3 (24 h)

12 µg/m3 (1 yr)

35 µg/m3 (24 yr)

NO2 40 µg/m3 (1 yr)

200 µg/m3 (1 h)

40 µg/m3 (1 yr)

200 µg/m3 (1 h)

40 µg/m3 (1 yr)

200 µg/m3 (1 h)

0,053 ppm (1 yr)

0,1 ppm (1 h)

Formaldehyde 0,081 ppm (30 min) 50 µg/m3

0,1 mg/m3 (30 min)

0,01 mg/m3 (24 h)

0,1 mg/m3 (30 min)

-
VOC - - - -
Radon 100 Bq/m3 100 Bq/m3 (new building), 400 Bq/m3 (built before 1992), 200 Bq/m3 (built after 1992) 400 Bq/m3 (indoor) 4 pCi/l = 148 Bq/m3

Thermal conditions

Several factors could result in variations in thermal conditions, including insulation and air tightness of the building envelope, indoor and outdoor temperature (T) and relative humidity (RH), orientation of the apartment (south/north), and occupants’ behavior (e.g., opening of windows, radiator valves adjustment). In Finland, for example, the national Housing and Health Guideline (Asumisterveysohje 2003) recommends that room temperature should be 21°C (acceptable temperature at 18°C) and that it should not exceed 23–24°C during the heating season. Too high a (room) temperature can increase occupants’ fatigue, reduce concentration and mental performance, and affect their health.

Indoor RH should be between 20% and 60%, although reaching the recommended range is not always possible due to climatic conditions. However, RH levels can rise due to insufficient ventilation and excessive drying of laundry inside. A too high a level of RH can lead to condensation on cold surfaces, increase the risk of mould growth, and even promote dust mite growth. On the other hand, RH may become low especially during the heating season. Overheating may further decrease humidity, potentially resulting in uncomfortably dry indoor conditions that can cause skin and respiratory track symptoms.

Carbon dioxide and carbon monoxide

Human beings are the main indoor sources of carbon dioxide (CO2) in most buildings. Hence, CO2 concentrations can be used as an indicator of occupancy and ventilation. High CO2 levels are associated with occupants feeling drowsy, getting headaches, or functioning at lower activity levels. CO2 levels exceeding 1000 ppm above the ambient level, which is about 380 ppm, may indicate insufficient ventilation and/or crowding, and be related to increased concentrations of indoor air pollutants and excess humidity. Too high CO2 levels can be lowered by enhancing ventilation.

The main indoor sources of carbon monoxide (CO) are incomplete combustions, e.g., gas and wood stoves, fireplaces, tobacco smoke, and automobile exhaust from outdoors through infiltration. Depending on the concentrations and exposure period, as well as age and health of the exposed, CO may cause headaches, fatigue, dizziness, confusion and nausea, as well as loss of consciousness and even death (at higher levels). According to the WHO guideline, maximum 8-hour mean of the CO level should be below 8.6 ppm.

Particulate matter

Indoor particle concentrations are related to both indoor emission sources (e.g., tobacco smoke, gas stoves, cooking, vacuuming) and outdoor (ambient) sources (e.g., suspended soils, pollen, and traffic exhaust). In addition to the type and strength of both indoor and outdoor sources, indoor concentrations are affected by building characteristics, air exchange rates (AER), air mixing characteristics, heating/cooling systems, and the presence of air filters.

Health risks are associated with exposure to particles that is less than 10 μm in diameter (PM10), more so for less than 2.5 μm (PM2.5). The EU and WHO guideline levels for PM10 range from 20 to 50 µg/m3 and for PM2.5 from 10 to 25 µg/m3, respectively. According to Finnish Housing and Health Guideline, the indoor air PM10 level (measuring period 24 hours) should be lower than 50 µg/m3. Whereas no Finnish guideline exists for PM2.5, it is suggested that the level should be less than 50 % of the PM10 level. High PM levels can be lowered for example by filtering the incoming air, avoiding smoking indoors and using the kitchen vent hood when cooking.

Nitrogen dioxide

Main sources of nitrogen dioxide (NO2) include vehicles, power stations, fuel or biomass burning, including controlled burning, and natural processes. The primary sources of NO2 indoors are combustion processes, such as unvented combustion appliances (e.g. gas stoves), vented appliances with defective installations, welding, and tobacco smoke.

The potential implications for health are respiratory irritation and aggravation of heart disease symptoms. Also, studies show a connection between breathing elevated short-term NO2 concentrations, and increased visits to emergency departments and hospital admissions for respiratory issues, especially asthma. The annual guideline (WHO) value for NO2 is 40 μg/m3.

Formaldehyde

Formaldehyde is an important chemical used widely, and the sources include building materials, smoking, and household products. Formaldehyde is also a by-product of the use of un-vented, fuel-burning appliances, such as gas stoves or kerosene space heaters.

Health effects of formaldehyde exposure (>0.1 ppm) include watery eyes; burning sensations in the eyes, nose, and throat; coughing; wheezing; nausea; and skin irritation. The odour of formaldehyde can be detected at level of 35 μg/m3. Finland has set up an indoor climate classification system, based on which the indoor climate is classified as S1 (individual indoor climate, formaldehyde target value 30 μg/m3), S2 (good indoor climate, 50 μg/m3), and S3 (satisfactory indoor climate, 100 μg/m3). According to Finnish Housing and Health Guideline, the formaldehyde level should not exceed 100 μg/m3.

Volatile organic compounds

Volatile organic compounds (VOCs) are widely used as ingredients in household products. BTEX compounds refer to the chemicals benzene, toluene, ethyl benzene and xylenes, and the sum of the concentrations of each of the constituents of BTEX is sometimes used to aid in assessing the relative risk or seriousness at contaminated locations and the need of remediation of such sites.

Health effects of VOC exposure include irritation in respiratory tracks as well as odor nuisance. There are no guidelines (for indoor air) for VOCs as a whole or for BTEX compounds. Benzene is known to be carcinogenic to humans, and WHO says that no safe level of exposure can be recommended.


Radon

Radon is an invisible, odourless, and tasteless radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils. Radon infiltrates typically from the soil below buildings, and the infiltration may react to the under pressure indoors, which may increase in some ventilation systems at higher ventilation rates.

The analyses indicate that the lung cancer risk increases proportionally with increasing radon exposure, which is the second cause of lung cancer after smoking. Most of the radon-induced lung cancer cases occur among smokers due to a strong combined effect of smoking and radon. The radon guideline values (EU/WHO) range from 100 to 400 Bq/m3.

References / links


Occupant health and well-being

Collecting information directly from the occupants is an important part of building and IEQ assessments. In multi-family buildings, collecting information from the occupants using structured interviews or questionnaires can be useful when assessing ways to improve occupants’ satisfaction with their housing conditions. However, such surveys should not include personal or health information, unless conducted by health professionals.

Collecting environmental data and human health data after contact with human participants requires consideration of the European Group on Ethics in Science and New Technologies. Where there is contact with human participants, data collection requires both an informed consent from each participant and a formal approval from an applicable ethics committee.

Due to numerous factors that influence human health and well-being, a large enough sample size is needed to draw conclusions about the empirical relationships between housing conditions and occupant health, which cannot be made on the level of individuals. The required sample size is primarily based on the need to have sufficient statistical power, so that one can be reasonably confident to detect an effect of a given size. There are many methodological difficulties inherent in assessing the health effects of housing. For example, response and follow up rates in studies are often low. Clinical studies may not be feasible.

Many studies have collected data from the occupants using structured interviews or questionnaires (picture 1), in which the occupants self-evaluate their health status. While occupant self-reporting is subjective and prone to reporting bias, there are, however, some ways to increase objectivity: e.g. using questions that specifically ask about matters that can be validated, such doctor diagnosed diseases, emergency room visits, and missed work/school days due to illness.

Drawing conclusions based on occupant health data requires careful analyses and interpretation. There are many confounding factors that have to be taken into consideration. National Institute for Health and Welfare has collected questionnaire data from random samples of 3000 household-dwelling units in 2007 and 2011 (so called "National housing quality, health and safety survey"). The results of this survey can be useful as reference material, regarding to housing and health conditions in Finland (Anttila et al. 2013).

References / links

• Anttila M, Pekkonen M, Haverinen-Shaughnessy U. Asuinympäristön laatu, terveys ja turvallisuus Suomessa 2007-2011 - ALTTI 2011 -tutkimuksen tuloksia

See also

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