Monitoring and results of the High Performance House

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Homestar rating

Based on the plans, the HIVE High Performance House received an 8 star Homestar™ design rating

 

Performance testing

Several tests of Warmframe™ walls and ceilings were conducted by InsulPro in the HIVE High Performance House.  The thermal testing results were verified by BRANZ.

 

Thermal testing

More than four testing runs were made on the walls and ceiling in various places. It proved difficult to get consistent heat in the living area, given the large amount of glazing, so tests were conducted in the hallway and bedrooms as well.  

Ceiling

90mm steel frame with high density R3.2 between trusses and R1.8 ceiling blanket

Overall R value 5.0-6.0

Walls

90mm steel frame with high density R2.5 insulation in the main wall cavity and R0.6 between battens.

Overall R value 2.7

Thermal imaging

HIVE thermal testingAs a final check InsulPro undertook thermal imaging of the walls.  Results showed:

  • A high level of consistency in insulation - almost no deficiencies in walls.  This indicates that the quality of insulation fitting is vital.
  • Products used proved being effective in steel frames high density allows for a good compression fit and ensures no gaps between insulation and framing.
  • Weak spots correspond with weaknesses in the construction detail such as wall-to-wall and wall-to-ceiling joints.
  • The best windows were no comparison to the wall in thermal performance. Living area design with excessive glazing was a weak spot for heating the living areas.

 

Live monitoring

Over the period that the house was open as a show home, it was monitored using SPLASH Monitoring (www.splashmonitoring.co.nz ).  This offered real-time animation updated every 10 seconds and available via their website. 

SPLASH monitoring results were analysed for June and July 2013.  While the house is not occupied, but acts as a show home - and is only open and heated between 12pm-4pm Wednesday - Sunday, the data does give some indication of how the house performed during the time of occupation, the effectiveness of the heating, and issues which will need to be considered by the occupiers of the house.  

The performance monitoring of the HIVE High Performance House indicated that it gave a good level of winter performance as a show home.   The house was dry and warm, and relatively easy to heat.

Relative humidity levels in both the living room and bedroom were very low - no level higher than 60% relative humidity was recorded, even when temperatures dropped substantially after several days of no occupancy.  This indicated no inherent problems with dampness in the dwelling fabric.  It doesn’t tell us a lot about moisture management during occupancy, however, as the major generators of moisture (bathroom and kitchen use) were not occurring in this house.

Temperature levels in the house reflected the high level of insulation and high quality windows and showed substantial solar heat gain on sunny days. 

Although the house was only occupied (and heated) for 4 hours/day 5 days/week the temperature profiles were better than many occupied and comprehensively heated homes.  In particular, the master bedroom was a warm room, and even when the house was unoccupied for 2 days, frequently stayed above recommended minimums (16 degrees) overnight.  The living room was colder and slow to heat up (which was to be expected with the large amount of glazing) but also frequently stayed above recommended minimum temperatures (18 degrees) for a large part of the night, and even when unheated often reached this temperature early in the afternoon. 

Solar gain in the north facing master bedroom was high. Even on cold days when the house was unoccupied, the bedroom would often heat up to warm temperatures with solar heating.  While this meant the bedroom was very warm in winter, there was a concern that the lack of shading on the northern façade and the absence of cross ventilation would lead to substantial summer overheating.  On some sunny days, even with the doors and windows open, the bedroom frequently recorded temperatures in the mid and late 20s and increasingly as the weather warmed, temperatures in the early 30s were reached.  Temperatures above 28 degrees could be regarded as overheating in a New Zealand context.  In part overheating could be addressed by the addition of shading and good thick curtains, both of which were not included in the show home.

The house proved to be somewhat slow to heat up with the pellet burner and there were some occupied periods where the living room has still not reached 18 degrees.  As a show home, the pellet burner was turned on at midday on the days when the house is occupied.  It would have been preferable for the thermostat and timer function to be used so that on cold days the pellet burner turned on before midday and heating was underway.


HIVE Homestar rating