*4.3.4. Bedroom performance variation*

Other than the probable identification of a poorly performing MVHR system, there are other factors for varying bedroom performance.

As highlighted in Figure 3, Bedroom 3 in House B SP1 produces unhealthy CO2 results. The room's size could be a contributing factor resulting in poor IAQ. Bedroom 3 has a volume less than half that of the largest bedroom (Table 2). It has no additional system design re‐ quirements, such as a larger supply vent or increased flow rate to provide more air changes. With the same occupancy levels the air will become polluted more rapidly than in a bed‐ room of a larger size, due to the smaller volume of air available for respiration.

It is also worth considering that the occupant slept with the door shut, magnifying the IAQ problem. There are no trickle vents between rooms and with the door shut there is no way of stale air leaving the room, this in turn inhibits supply flow.Bedroom 3's performance is of specific interest because it has the most potential to be used as a nursery. As previously mentioned in the IAQ of these spaces must be excellent as it is a time when childhood ill‐ ness/IAQ related health issues are most common.

Significant evidence explaining reasons for the improvement in CO2levels can be sought from a report written following an inspection of the MVHR system in both houses, by the installer, subsequent to the completion of the first study period. The report identified a num‐

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

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In House A it was observed that 125mm ducting had been used in the roof space, but that the majority of ducting installed was only 100mm. This potentially led to the unit running at higher pressure than it was designed to, although no increase was specifically noted. In House B, however, the system was measured to be running at an increased pressure. Higher pressures impact on air flow and created the potential for fans to stall, resulting in reduced

There were several reasons for the high pressure within the system of House B. As well as the extensive use of 100mm ducting, there were also additional bends compared to that of the ducts in House A. In addition the ducting had been connected in the wrong position to the MVHR unit. This contributed to the high pressure as well as reducing the performance of the system. Areas of ducting were also found to contain remnants from the internal fix out of the house, hindering air flow. Other ducts had been squashed. Both faults increased pressure within the system. The filters within the unit were seen to be dirty and in need of cleaning/replacement. This factor would have resulted in increased resistance adding to the high pressure within the system. The build up of dirt would have reduced the filters air pu‐ rifying efficiency resulting in increased levels of contaminants being circulated throughout the house. Extract flow rates in the rooms were measured at low levels because the system was running poorly, this would result in polluted air being removed from rooms at a much

It seems reasonable to conclude that these works have improved the performance of the sys‐ tem, but that concerns remain in regard to the levels of IAQ that are experienced by occu‐

This project was a building performance evaluation of an adaptive rehabilitation project on a Category B listed 19th Century stone tenement located within the World Heritage Site of Edinburgh's Grassmarket. Working within the constraints of its historical significance and limited budget (a registered social landlord as Client) and end user group, this project has

To assess the performance of this building MEARU undertook a programme of monitoring and evaluation over a three-week period during March 2011(from 17.03.11 to 12.04.11).

supplemented with an analysis of energy demand and acquisition of qualitative data through semi-structured interviews of the occupants, and observations by the surveyors to

C. Environmental monitoring was

sought to create an energy efficient solution for its sustainable rehabilitation.

Average external temperatures during this period were 9 o

provide an overview of building performance.

ber of defects, which were rectified between SP1 and SP2.

slower rate than necessary during inhabitation.

pants, particularly during peak conditions.

**5. Case study 2: Gilmores close**

ventilation.

**Figure 8.** Window Opening, SP1, House A, Bedroom 2

In the same study Bedroom 2 in House A also performs poorly in relation to IAQ. Bedroom 2 has a volume of approximately 28m3 compared with 17m3 in Bedroom 3. This room was heavily ventilated naturally over SP1 (Table 3). By looking at how conditions changed dur‐ ing each recorded window opening period it is assumed that without this additional natural ventilation Ta and CO2levels would have been considerably higher. Its counterpart in House B was only subject to roughly four hours of natural ventilation compared with 30, but per‐ formed considerably better, although maximum and minimum values were similar. It is possible that in House B the occupant slept with their bedroom door ajar opposed to that of House A. This is unconfirmed. The results produced for this room during SP1 would lean towards House B having producing more acceptable IAQ and are backed up by qualitative assessment which found occupants rated House B's IAQ to be superior to that of House A.

In addition to the examples discussed it is worth noting that the attic rooms seem to perform relatively well in each case, even with House A having double the occupancy level. This could be due to Bedroom 4's large volume and also its proximity to the MVHR unit resulting in short‐ er duct lengths and therefore better flow rate. The room's location near to the unit may also ex‐ plain why in the qualitative assessment made by an occupant it was stated that the fan was very obvious and noisy in the attic bedroom. With this is mind, the position of MV supply vents and the noise levels they produce should be considered to the same extent, especially as the air tight construction results in the home being extremely quiet in general.

### *4.4.4. Study period variation*

The substantial difference shown in the results, between the chosen examples, highlights a clear improvement in CO2levels between SP1 and SP2.The qualitative IAQ results recorded support the quantitative results. The inhabitants deemed the air to be of greater satisfaction, freshness and circulating more frequently within the second study period.

Significant evidence explaining reasons for the improvement in CO2levels can be sought from a report written following an inspection of the MVHR system in both houses, by the installer, subsequent to the completion of the first study period. The report identified a num‐ ber of defects, which were rectified between SP1 and SP2.

In House A it was observed that 125mm ducting had been used in the roof space, but that the majority of ducting installed was only 100mm. This potentially led to the unit running at higher pressure than it was designed to, although no increase was specifically noted. In House B, however, the system was measured to be running at an increased pressure. Higher pressures impact on air flow and created the potential for fans to stall, resulting in reduced ventilation.

There were several reasons for the high pressure within the system of House B. As well as the extensive use of 100mm ducting, there were also additional bends compared to that of the ducts in House A. In addition the ducting had been connected in the wrong position to the MVHR unit. This contributed to the high pressure as well as reducing the performance of the system. Areas of ducting were also found to contain remnants from the internal fix out of the house, hindering air flow. Other ducts had been squashed. Both faults increased pressure within the system. The filters within the unit were seen to be dirty and in need of cleaning/replacement. This factor would have resulted in increased resistance adding to the high pressure within the system. The build up of dirt would have reduced the filters air pu‐ rifying efficiency resulting in increased levels of contaminants being circulated throughout the house. Extract flow rates in the rooms were measured at low levels because the system was running poorly, this would result in polluted air being removed from rooms at a much slower rate than necessary during inhabitation.

It seems reasonable to conclude that these works have improved the performance of the sys‐ tem, but that concerns remain in regard to the levels of IAQ that are experienced by occu‐ pants, particularly during peak conditions.
