Heat Pump Not Keeping Up? A Glenmore Kelowna Sizing Case Study
A room-by-room CSA F280-12 calculation for a home in Glenmore, Kelowna found that the open living room, kitchen and front entrance had a combined design heating load of 23,880 Btu/h. The entrance accounted for 9,360 Btu/h of that total, increasing the heating requirement by approximately 64% compared with the living room and kitchen alone.
The homeowner’s recently installed ductless heat pump was not keeping the living room comfortable. Thrive Energy’s calculation gave the HVAC contractor a clearer picture of the connected area’s heating and cooling requirements, so they could compare those loads with the installed equipment.
Calculation by Brett Tracy, Registered Energy Advisor, Thrive Energy Inc., June 2026.
Project at a glance
| Project detail | Description |
|---|---|
| Location | Glenmore, Kelowna, BC |
| Project type | Existing home with a recently installed ductless heat pump |
| Service | Independent room-by-room CSA F280-12 heat-load calculation |
| Calculation date | June 2026 |
The problem with the living room heat pump
A local HVAC contractor had installed a ductless heat pump in the Glenmore home, but the indoor head serving the living room was not keeping the space comfortable. Rather than estimate what capacity the room needed, the contractor brought Thrive Energy in for an independent calculation.
The question was straightforward: what heating and cooling loads did this area of the home actually have? Answering it required looking at the building’s construction, air leakage and layout, including the spaces connected to the living room.
What Thrive Energy measured
Thrive scanned the home using Properate Stride, which uses LiDAR to measure rooms, then checked and adjusted the measurements on site. These measurements provided the geometry for the room-by-room calculation.
The model incorporated the building conditions found in the home:
- 2×4 and 2×6 insulated walls
- Double-glazed metal-frame windows
- An uninsulated slab
- The layout of the living room, kitchen and adjoining entrance
- Measured airtightness of 4.5 air changes per hour at 50 Pascals (ACH50)
The calculation used Kelowna design conditions of −17°C for winter heating and 33°C for summer cooling for this project. These are the outdoor conditions used to calculate the design loads, rather than a description of the weather on the assessment day.
Using the home’s measured layout and airtightness helped establish building-specific inputs instead of relying only on floor area or assumptions about air leakage.
The entrance added a substantial heating load
The key finding concerned the area the living room head was expected to serve. The front entrance was open to the living room and kitchen, so its load also needed to be considered when evaluating the connected zone.
The living room and kitchen had a calculated heating load of 14,520 Btu/h. The entrance added another 9,360 Btu/h, bringing the combined heating load to 23,880 Btu/h.
Adding the entrance increased the heating load by approximately 64% over the living room and kitchen alone. A sizing assessment that considered only those two spaces would leave out a substantial part of the connected area’s demand.
Heating and cooling loads for the open living area
| Space | Heating load | Cooling load |
|---|---|---|
| Living room and kitchen | 14,520 Btu/h | 19,618 Btu/h |
| Front entrance | 9,360 Btu/h | 7,707 Btu/h |
| Total for the open area | 23,880 Btu/h | 27,325 Btu/h |
Thrive showed the entrance and living area separately in the report so the contractor could see each space’s load and their combined requirement. That distinction matters: where an indoor head is mounted does not necessarily define the entire area it is expected to heat and cool.
The combined load gives the contractor a basis for evaluating the zone. Equipment selection also needs to consider the unit’s performance under the relevant outdoor conditions and how conditioned air reaches the connected spaces.
What the full home calculation showed
The assessment covered every other room in the house as well as the living area. The full report recorded the following whole-home figures:
| Whole-home result | Reported value |
|---|---|
| Total building heat loss | 56,998 Btu/h |
| Nominal cooling capacity | 55,579 Btu/h |
These whole-home figures relate to the entire building. They should not be treated as the capacity required from the living room head alone.
What the contractor received
The contractor received a room-by-room CSA F280-12 report showing the heating and cooling loads for the space where the homeowner was experiencing discomfort. They could use the report to compare the calculated demand with the installed equipment’s performance data and discuss next steps with the homeowner.
The report provided the design loads needed for that comparison. Evaluating the heat pump’s capacity at the project’s winter design temperature, alongside the installation and air distribution, would help the contractor determine the appropriate response to the comfort complaint.
What homeowners can learn from this Kelowna project
Consider connected spaces. An entrance, kitchen or hallway that is open to the living area can add heating and cooling demand. Discuss the whole area the indoor unit is expected to serve with the contractor.
Use building-specific information. Floor area alone does not describe the effects of windows, exterior doors, insulation or air leakage. A room-by-room calculation accounts for more of the conditions that affect demand.
Calculate before selecting equipment. If you are planning a heat-pump installation or replacement, obtaining the design loads before equipment selection gives the contractor a stronger basis for comparing suitable systems.
Use an independent assessment when performance is disappointing. A load calculation can help clarify the home’s requirements and support the conversation between homeowner and contractor. The contractor still needs to evaluate the equipment and installation when determining why a system is not maintaining comfort.
Book a heat-load calculation with Thrive Energy
If you are planning a heat-pump installation or investigating a system that is not keeping up, Thrive Energy provides CSA F280-12 heat-loss and heat-gain calculations for new and existing homes throughout the Okanagan and BC Interior.
Contact Thrive to discuss the plans, on-site measurements and report needed for your project.
Learn about CSA F280 heat-load calculations and request an assessment
Call 778-867-0242 or email office@thriveenergyinc.com.
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