New residential; construction, additions, alterations, renovations or repairs shall comply with one of
the following three paths for energy conservation: Prescriptive, Alternative or Performance.
It is mandatory that you also comply with the Air Leakage, Moisture Control, and HVAC
Requirements regardless of which path is chosen.
THE DESIGN CRITERIA FOR DOUGLAS COUNTY IS CLIMATE ZONE 5B
(ALL R-VALUES ILLUSTRATE MINIMUMS / ALL U-VALUES ILLUSTRATE MAXIMUMS)
1. PRESCRIPTIVE PATH
0.35 0.60 R-38 R-20 or
R-13/17 R-30 (B)
(A) “13+5” means R-13 plus R-5 insulated sheathing. If structural sheathing covers 25% or less of
the exterior, insulating sheathing is not required where structural sheathing is used. If
structural sheathing covers more than 25% of exterior, structural sheathing shall be
supplemented with insulated sheathing of at least R-2.
(B) The first R-Value applies to the continuous insulation (CI), the second to framing cavity insulation; either
insulation meets the requirement.
(C) R-15 is required for a heated slab; insulation is required to continue 2 feet horizontal or vertical.
(D) The second R-Value applies when more than half the insulation is on the interior of the mass wall.
A minimum of 50% of the lamps in permanently installed lighting fixtures shall be high-efficacy lamps.
2. ALTERNATIVE PATH
Douglas County approves the use of a national, state or
local energy efficiency program that exceeds the energy
efficiency required by this code. These programs include:
Air leakage - Mandatory
The building thermal envelope shall be durably sealed to
limit infiltration. The following shall be caulked, gasketed,
weather stripped or otherwise sealed with an air barrier
material, suitable film or solid material:
1. All joints, seams and penetrations.
2. Site-built windows, doors and skylights.
3. Openings between window and door assemblies
and their respective jambs and framing.
4. Utility penetrations.
5. Dropped ceilings or chases adjacent to the
thermal envelope (insulated wall or ceiling).
6. Knee walls.
7. Walls and ceilings separating a garage from
8. Behind tubs and showers on exterior walls.
9. Common walls between dwelling units.
10. Recessed lighting installed in the ceiling shall be
sealed to limit air leakage between conditioned
and unconditioned spaces by being IC/Airtight
rated can or enclose an IC rated fixture in an air
11. Rim joists insulated and include air barrier.
12. Any other source of infiltration.
Moisture Control - Mandatory
Walls, floors and ceilings not ventilated to allow moisture
to escape shall be provided with an approved vapor
retarder. The vapor retarder shall be installed on the
warm-in-winter side of the thermal insulation with a perm
backed insulation or a 4 mil plastic.
3. PERFORMANCE PATH
Compliance based on simulated energy performance
requires that a proposed residence (proposed design) be
shown to have an annual energy cost that is less than or
equal to the annual energy cost of the standard reference
design (Standard Design). Energy prices shall be taken
from the Department of Energy or Energy Information
Administration’s State Energy Price and Expenditure
Report. Specific Software, calculation procedures and
reports are required. Please speak with a Douglas County
plans examiner if you elect to use this path.
Heating and Cooling Systems (HVAC) - Mandatory
Supply and return ducts located in an unconditioned attic
shall be insulated with R-8.
Supply and return ducts located in an exterior wall or floor
shall be insulated with R-6.
All supply, return, filter boxes and plenums shall be sealed
with a UL181 listed tape or mastic.
Mechanical and circulating hot water systems:
Mechanical system piping (HVAC piping) conveying fluids
greater than 105o F or less than 55o F shall be insulated to
R-2 minimum. Typically, this will apply to refrigerant piping
and water piping for hydronic heating systems.
All circulating service hot water piping shall be insulated to
at least R-2. Circulating hot water systems shall include an
automatic or readily accessible manual switch that can
turn off the hot water circulating pump when the system is
not in use.
Equipment and duct sizing:
Heating/cooling equipment and the duct system shall be
sized in accordance with Manual J and Manual D.
Mechanical contractors shall be responsible for sizing
100 Third Street · Castle Rock, Colorado 80104 · 303.660.7497 · Fax 303.479.7271
Required Residential Inspections
1. Foundation Insulation Inspection (Insp. # 114)
For insulation that will be covered by backfill or structural floors. The Mono slab and post-tension slab
insulation shall be inspected before the placement of concrete.
2. Fenestration (Insp. # 106)
For replacement glazing (windows, skylights, sliding doors etc.). Factory labels must remain on the
glazing that show fenestration, solar heat gain and air leakage as required in Section 402.3 and Section
3. Thermal Envelope (also known as Exterior House Wrap) (Insp. # 132)
All house wrap, air barrier or suitable film shall be installed in accordance manufacturer’s
recommendations, including overlapping, inside corners and taping. All penetrations through the building
wrap have been sealed. Window and door flashing has been installed in accordance with manufacturer’s
4. Rough Energy Compliance (Insp. # 129)
All joints, seams and penetrations shall be caulked, foamed, or otherwise gasketed to prevent air
leakage. Factory labels must remain on the glazing to show fenestration, solar heat gain and air leakage.
Air barriers are in place including rim joists. Air tight recessed lighting in attic spaces, required dampers
(mechanical or gravity) and insulation behind junction boxes in exterior walls shall be in place for this
-See Air Leakage (Mandatory)-
5. Insulation – Mechanical Systems (Insp. # 122)
This inspection shall be requested after Rough Frame Inspection has been approved. This inspection is
to verify that all supply and return air ducts outside the conditioned space are insulated in accordance
with Section 403.2.
All Mechanical and Circulation hot water systems shall be insulated in accordance with Section 403.3 and
-See Heating and Cooling Systems (Mandatory)-
6. Insulation (Insp. # 36)
This inspection includes all cavity or continuous (blanket) insulation that will be concealed. For blown in
attic insulation, baffles at soffit vents and inch markers every 300 sq. ft. shall be installed at the time of
-See Moisture Control (Mandatory)-
7. Final Energy Compliance (Insp. # 109)
A permanent certificate shall be posted in the area housing the mechanical equipment. The certificate
shall be completed by the builder or registered design professional. The certificate shall list the R-values
of insulation installed in or on ceiling/roof, walls, foundation (slab, basement wall, crawlspace wall and or
floor) and ducts outside conditioned spaces; U-factors for fenestration. The certificate shall list the type
and efficiency rating of heating, cooling and service water heating equipment. Crawl space and
unfinished basement walls blanket insulation may be inspected at this time.
A ladder shall be provided by the permit holder for access to attic spaces containing blown in
insulation and or mechanical equipment.