WEC-Heating_System_Sizing HitchensSimple Heating System Size: Washington State
This heating system sizing calculator is based on the Prescriptive Requirements of the 2015 Washington State Energy Code (WSEC) and
ACCA Manuals J and S. This calculator will calculate heating loads only. ACCA procedures for sizing cooling systems should be used to
determine cooling loads.
Please fill out all of the green drop -downs and boxes that are applicable to your project. As you make selections in the drop -downs for each
section, some values will be calculated for you. If you do not see the selection you need in the drop -down options, please call the WSU
Energy Extension Program at (360) 956-2042 for assistance.
Project Information
Contact Information
The Hitchens Residence
Kearsley Homes
17901 Vista Del Mar
6630 Norma Beach Road Edmonds, WA 98026
Edmonds, WA 98026
(425) 478-6380 r(a)kearsleyhomes.com
Heating System Type: Electric Heat Pump
To see detailed instructions for each section, place your cursor on the word 'Instructions".
Design Temperature
Design Temperature Difference (AT)
AT = Indoor (70 degrees) - Outdoor Design Temp
Area of Building
Conditioned Floor Area
Instructions Conditioned Floor Area (sq ft)
4,759
Average Ceiling Height
Conditioned Volume
Instructions Average Ceiling Height (ft)
9.0
42,831
Glazing and Doors
U-Factor
X Area =
UA
Instructions
.30
1,481
444.21
Skylights
U-Factor
X Area =
UA
Instructions
0.50
---
Insulation
Attic
U-Factor
X Area =
UA
Instructions
.026
366
9.52
Single Rafter or Joist Vaulted Ceilings
U-Factor
X Area
UA
Instructions
.027
2,277
61.48
Above Grade Walls (see Figure i)
U-Factor
X Area
UA
Instructions
.056
2,631
147.34
Floors
U-Factor
X Area
UA
Instructions
.029
290
8.41
Below Grade Walls (See Figure 1)
U-Factor
X Area
UA
Instructions
.042
380
15.96
Slab Below Grade (see Figure 1)
F-Factor
X Length
UA
Instructions
.303
43
12.88
Slab on Grade (see Figure 1)
F-Factor
X Length
UA
Instructions
.36
182
65.52
Location of Ducts
Instructions No ducts
Duct Leakage Coefficient
1.00
Figure 1.
Above Grade
Sum of UA 765.31
46
Envelope Heat Load
35,204 Btu / Hour
Sum of UA X AT
Air Leakage Heat Load
21,278 Btu / Hour
VolumeX 0.6XOTX.018
Building Design Heat Load
56,483 Btu / Hour
Air Leakage + Envelope Heat Loss
Building and Duct Heat Load
56,483 Btu / Hour
Ducts in unconditioned space: Sum of Building Heat Loss
X 1.10
Ducts in conditioned space: Sum of Building Heat Loss X 1
Maximum Heat Equipment Output
70,603 Btu / Hour
Building and Duct Heat Loss X 1.40 for Forced Air Furnace
Building and Duct Heat Loss X 1.25 for Heat Pump
(07/01/13)