**4.1. Construction**

ed and the current consensus of opinion is that levels above 1000ppm are linked to poor occupant health [21]. Where concentrations greater than 1000ppm are experienced the rate of air change is insufficient and the potential for culmination of internal pollutants is increased with an associated impact on occupant health. Examples within domestic contexts include vol‐ atile organic compounds (VOC), which act as allergens and respiratory and dermal irritants [22].With low air change rates there is also a well-defined risk of interior moisture vapour build up which brings with it its own set of health implications. Vapour pressures over 1.13kPa have been identified as promoting the growth of dust mite populations [23] which have, in turn, have been found to have a causal relationship with development of asthma in susceptible children [24]. With high vapour pressures there is also an associated risk of fugal growth and an increase in the levels of fungal spores, microbial bodies and other pathogens which can be detrimental to the health, particularly to the ever increasing atopic portion of the population. In addition to this, increased relative humidity has also been found to increase health impact from non-biological aerosols as it increases the rate of off gassing of water-soluble chemicals

In both these case studies a key component to address the issue of ventilation and energy use was the inclusion of Mechanical Ventilation Heat Recovery Systems (MVHR). The prin‐ ciple of these systems is that poor quality, but relatively high temperature internal air is me‐ chanically extract from spaces in the dwelling, typically spaces which contain 'problem' air such as high moisture content or smells from kitchen and bathrooms. This air is passed through a heat exchanger during which colder fresh air from the outside is warmed by the recovered heat before being delivered to the dwelling. In theory should satisfy the needs of both energy conservation and IAQ to produce a sustainable solution. Accordingly the dis‐

The methodology in both case studies was broadly similar. Quantitative data on tempera‐ ture, humidity and CO2 levels was collected using Eltek GD-47 Transmitters linked to Eltek RX250AL1000 Series Squirrel Data Loggers. This was supplemented by Gemini TinytagPlus Data Loggers for temperature and humidity some rooms without a power supply (bath‐

The Glasgow House was unusual in that as demonstration houses they did not have occu‐ pants. MEARU in conjunction with GHA developed a methodology for scenario testing whereby volunteers occupied the houses for two-week periods during which they were asked to follow set occupancy 'scripts' for behaviour. Heating and environmental controls were fixed in the script and users were asked not to change these. Thus occupancy and be‐ haviour could be tightly controlled, allowing an examination of the environmental perform‐

In the Glasgow House, additional qualitative information was gathered using occupant dia‐ ries, record sheets for key activities such as fan operation and boost switch use, cooking, and window opening. The inhabitants of the house were each given diaries to record their day-

cussion below makes particular reference to the performance of these systems.

such as formaldehyde [25].

144 Sustainable Energy - Recent Studies

**3. BPE methodology**

rooms and toilets).

ance under known conditions

The two semi detached houses were built in 2010 by City Building (CB) in partnership with the GHA. They were designed to provide comfortable and flexible living for low income families with an aim of costing no more than £100 per year to heat. The houses are of similar layout and consist of a porch, kitchen/dining/living area, a utility room/WC, four bedrooms, a bathroom and garden.

The design incorporated high levels of thermal efficiency using a Thermoplan clay block with external insulation, highly insulated roof cassettes and high performance windows, thermal mass, airtight construction (0.4 ach), sunspaces, solar thermal hot water collectors, mechanical ventilation heat recovery, low energy lighting and high efficiency appliances (House A). The comparison house is identical house except the clay block is replaced with a more conventional highly insulated timber frame system which is the standard form of con‐ struction used by City Building.

A series of scenarios were proposed to examine how these houses performed in use with ac‐ tual occupants. Findings from two separate periods of BPE, in February and December 2011 are described here. In both cases four occupants inhabited each dwelling. They were to sim‐ ulate an average family living pattern and were given prescribed scripts on occupancy.

Heating is by a high efficiency gas boiler and radiators. Hot water heating is supplemented by the use of a solar hot water system. Ventilation is by a MVHR system, extracting air from the kitchen and bathrooms spaces and supplying a balanced flow of air to the living room and bed‐ rooms. The temperature of the house was pre-set using the main thermostat and by the indi‐ vidual thermostats on the radiators in each room. The MVHR system was inspected visually and the filters changed if necessary. Electricity and gas meter readings were made at the start and end of the monitoring process in each dwelling to record energy consumption.

lected periods (SP1 and SP2) from each study were sufficient to provide adequate data for

The February study monitored a period of non-occupancy prior to SP1 commencing. This data provides a valuable 'control' period (CP) which can be utilised to understand how the house performed in relation to IAQ when uninhabited. Although the studies were run dur‐ ing different months, they were both in the winter period of the same year. Average external

During study periods occupancy levels in the houses remained constant. The houses' flexi‐ ble layout resulted in sleeping arrangements varying depending on how the show home

Bedroom 1 Double 1 Double 1 Bedroom 2 Double 1 Double 1 Bedroom 3 - 0 Single 1 Bedroom 4 Twin 2 Double 1

When assessing the results it should be noted that in House A, Bedroom 3 was set up as a study/office and was not used for sleeping. As a consequence, the occupancy of House A, Bedroom 4 was double that of House B. Data collected from House A, Bedroom 3 is still rel‐ evant, although the results will not warrant accurate comparison with House B, Bedroom 3. The data can be viewed to see how the room performs when uninhabited, similar to the con‐ trol period mentioned previously. House A, Bedroom 3 can be compared between the two study periods, however. It is worth mentioning that each occupant will not have spent the same amount of time in their bedroom and sleeping patterns will have varied. Similarly, room occupancy level throughout the house may have varied from time to time, depending

on occupant activities and interaction. High occupancy room levels ≥ 3 inhabitants.

When evaluating the data it is essential to consider each bedrooms qualities, in order to

The room on the 2nd floor, in the attic space, is the largest of the bedrooms. Bedroom 3 is the smallest. Bedroom sizes vary slightly between the two houses. This is due to the construc‐ tion types, which alter the wall build up, affecting internal space a little. The houses have

C in SP1 and 3.3 0

**House A House B Type Occupancy Type Occupancy**

C in SP2. The studies can be

http://dx.doi.org/10.5772/51900

147

The Role of Building Users in Achieving Sustainable Energy Futures

analysis and comparison.

had been set up. (Table 1).

temperatures during this period were 5.5 0

**Table 1.** Occupant Sleeping Arrangements, SP 1 & 2, House A

make fair comparisons. (Table 2).

identical plan configurations.

compared reasonably accurately in relation to this slight inconsistency.

**Figure 1.** The Glasgow House, Ground Floor Plan
