Energy Code Guide for New Home Construction

☐ Windows Continued

Some manufacturers label their products with serial numbers or

other data that can be used to track down the efficiency rating.

If there is no documentation of the U- factors, try contacting the

customer service department of the window manufacturer to

confirm the efficiency of the installed products.

☐ Heating and Cooling Systems

Was the system sized in accordance with ACCA Manual S & J or

another approved heating and cooling equipment sizing

method? These calculations consider house tightness, insulation

levels and window placement efficiency. A system sized too

small could result in an uncomfortable home; if too large, it may

cycle on/off more than necessary which may shorten the life of

the equipment.

☐ Programmable Thermostat

Programmable thermostats are required on forced air

(furnaces). Which can provide an energy savings of about 10

percent when used as recommended. Hot water boilers must

have an outdoor setback control that decreases the boiler

water temperature based on the outside temperature.

☐ Heating Ducts

Check that all the seams in the

ductwork are sealed with mastic or

approved tape. Regular duct tape

is not approved. Leaky ducts can

be responsible for 10-30% of the

energy loss in a home. The code

requires the entire duct system be

tested for tightness if any part of the

ductwork is in an unheated/unconditioned part of the house,

such as an unheated attic or garage. The test results should be

listed on the energy component label. Supply ducts located

outside of the conditioned part of the house must be insulated

to at least R-8 and return ducts to at least R-6.

☐ Air Sealing and Ventilation

The energy code requires air sealing around windows, doors,

electrical boxes on exterior walls, and ceilings and openings

where pipes and wires pass through the building shell. Air

leakage is often responsible for 10 to 30 percent of total home

energy loss. Check to see if pipes, wires and utility lines, and

other openings have been sealed. Most of the air leakage sites

will be hidden in the attic, walls, and floor. Because the house is

sealed for comfort and efficiency, it is important to ventilate the

house in a controlled way.

☐ Air Sealing and Ventilation Continued

Code-required mechanical ventilation options range from a

centrally located efficient (bath) fan to a heat recovery

ventilation system (HRV) that bring fresh air into the house while

recovering about 70 percent of the heat from the stale air that is

being drawn out of the house.

☐ Blower Door Test

Blower door testing is required to confirm the

air sealing requirements have been met. The

test results should be listed on the Energy

Code Compliance Label and must be 4 air

changes per hour at 50 Pascal pressure

(listed as ACH50) or less. A blower door is a

large fan assembly, temporarily placed in an

exterior doorway, which draws air out of the

house. Instruments measure the amount of

air flow and determine the air leakage rate of the house. Very

efficient tight houses may have leakage rates of only 0.6 to 2.5

ACH 50.

☐ Infrared Camera Investigation (Optional)

An infrared (IR) camera shows the

temperature of the house’s surfaces.

Improperly insulated areas will appear

colder than expected in winter and

warmer than expected in summer.

Consider having an IR investigation to

confirm the house has been properly

insulated. An IR investigation

conducted with a blower door analysis can detect air leakage.

☐ Energy Efficiency Lighting

The code requires all permanent lighting fixtures have high

efficiency bulbs, kitchen appliances are exempt.

For more information contact the Montana Energy Office at the

Montana Department of Environmental Quality at 406-444-0281

or visit our website at deq.mt.gov/Energy.

Printed on recycled paper

Energy Code Guide

for New Home

Construction

Use this checklist to help ensure your new home is

comfortable, healthy, and energy code compliant.

Common Air Leaks:

Air leaking into the house

Air leaking out of the house

Updated August 2022

Ductwork

Blower door

Air leakage

through

recessed

light fixture

Energy Code Guide for New Home Construction

Montana’s energy code provides minimum requirements for the

efficient design and construction of new and renovated houses.

All new Montana houses, regardless of location, must meet the

requirements of the state energy code.

You can use this guide to verify a few of the energy code

requirements. While the guide does not include every

requirement, it will help you assess a home and make an

informed decision about the quality of construction and

likelihood the home will be energy efficient. Code compliance

can be accomplished by completing basic air sealing

requirements and following an energy code path of prescribed

insulation levels, and window/door efficiencies or by using

REScheck™. REScheck™, a free computer modeling analysis

software, is available from the U.S. Department of Energy and

may be enlisted to meet compliance. REScheck™ is available to

download at energycodes.gov. Energy code path levels are

listed on the energy efficiency components label on the next

page.If you don’t feel comfortable using this guide, and for a

more complete investigation, consider having a qualified

independent third party complete a code compliance

checklist. An example checklist can be found at

deq.mt.gov/Energy.

☐ Energy Code Compliance Label

Check that a completed energy code compliance label has

been placed on or in the electrical breaker panel. The label

should list the insulation levels, as well as efficiency ratings of the

installed windows, doors, water heating, and heating/cooling

equipment. It is also a way for the home builder to comply with

Montana law, which requires builders to certify their homes meet

the statewide minimum energy code standards.

☐ Ceiling and Attic Insulation

The energy code path requirement for ceilings and attics is R-49

insulation, which is about 15 inches of fiberglass or cellulose

insulation. R-38 meets code if that level is achieved over the

entire ceiling/attic when an energy truss is used. Check that the

attic access hatch/door is insulated, and sealed.

☐ Above-Grade Wall Insulation

The energy code path requires R-21 for above- ground walls. A

REScheck™ analysis may allow a lower level. If less than R-21, ask

to see a copy of the REScheck™ analysis.

Below is a sample energy code compliance label with filled in

path levels:

☐ Basement Walls

Check to see if the basement walls are insulated; finishing is not

required. The insulation can be placed on the outside, inside, or

combination. The energy code path requires a continuous layer

of R-15, such as a layer of foam installed on the foundation wall,

or R-19 if the insulation is placed in a framed wall.

☐ Basement Walls Continued

The rim/floor joist is located

where the floor meets the wall

and should be insulated and

have an air barrier, usually

spray foam or foam boards

sealed in-place. If lower R-

values are listed, ask to see a

copy of the REScheck™

analysis, confirming code compliance.

☐ Crawlspace

In a heated crawlspace any crawlspace vents open to the

outside should be sealed

shut. Check that the floor

above the crawlspace or

the foundation walls are

insulated. Typically, the

walls are insulated,

creating a heated

crawlspace and the

ground is covered with a

moisture barrier, usually plastic sheathing sealed around the

edges. The insulation should be installed without gaps. The

rim/floor joist located where the floor meets the foundation wall

should be insulated and have an air barrier. The air barrier is

usually spray foam or foam boards sealed in-place. If the

crawlspace is heated, any crawlspace vents should be sealed

shut. A heated crawlspace should have some air flow such as a

small exhaust fan drawing air out, or a register in the heating

duct supplying air and an opening/transfer grill in the floor

connecting the crawlspace to the upper floor.

☐ Windows

Check the energy components label for the U-factor rating for

the windows. The lower the U-factor, the

better. U-factors generally range from

.20 (little heat loss) to .50 (high heat loss).

The energy code path requires U-.30 or

better. A REScheck™ analysis may allow

a higher U-value.

Insulated framed wall with

rim joist foam sealed at

Crawlspace: foundation

continuous wall insulation with

rim joist foam seal at arrow