Town of Telluride Energy Conservation Code

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Link to adoption language, Article 9…

effective February 18, 2020

Mandatory ERI path

ERI 61 (zone 6)


c) Residential Energy.

(1) Amend Section R401.2 “Compliance” to read:

All new buildings and any building having an addition of 1000 square feet or greater shall comply with Section R406. All other buildings shall comply with one of the following:

The remainder of the section remains unchanged.

(2) Add new Section R402.2.14 “Exterior walls” to read:

R402.2.14 Exterior Walls. Recess step lights are not permitted in exterior building walls except where the required R-value is met for the wall assembly.

(3) Add a sentence to Section R402.4.5 to read:

Recessed can lights are allowed in ceiling-roof assemblies only if the required R-value of insulation can be met between the top of the fixture and the roof decking material.

(4) Amend Table R402.4.1.1 by adding to the Insulation Installation Criteria for the Walls Component:

Wood or Engineered Headers-R-10 wherever possible.

Steel Header – R-10 with insulation provided on both the exterior and/or the interior sides of the steel if possible, to maintain a continuous thermal barrier.

(5) Amend Section R403.5.3 to read:

R403.5.3 Hot water pipe insulation (Mandatory). Insulation for hot water piping with a thermal resistance, R-value, of not less than R-3 shall be applied to the following:

Items 1 through 7 remain unchanged.

8. Hot water line piping shall not be placed in an exterior wall to the extent practical. When not practical as determined by the Building Official, hot water piping may be placed in an exterior wall provided the required insulation R-value of the wall is provided in between the piping and the exterior of the wall.

9. An insulating blanket shall be provided that covers entire water tank fastened with appropriate tape.

(6) Add a last sentence to Section R403.7 to read:

Systems shall be designed by a certified Mechanical Engineer for single family residential structures greater than 2,000 sq. ft. of gross floor area including the basement area.

(7) Amend Section R406.1 to add to the following as the last sentence:

ERI refers to the ERI Home Energy Rating System (HERS) score.

(d) Additional Requirements for Residential and Commercial Buildings.

(1) Cement. All cement used within the Town shall be mixed with western coal fly ash, except such a mix is not required for exterior slabs.
(2) Low Volatile Organic Compounds (“VOC”). The general contractor and the property owner shall sign the Homeowner VOC Awareness Checklist provided by the Town prior to the issuance of a certificate of occupancy for a project.
(3) Energy Star Ratings. Energy Star rated appliances, exhaust fans and light fixtures shall be installed.
(4) Exterior vegetation irrigation systems shall be installed with a moisture sensor and timer to control irrigation.

(5) Pools and Spas (Hot Tubs).

a. Exterior swimming pools are prohibited in Telluride unless otherwise approved by the Planning and Zoning Commission pursuant to the use permitted on review development review process contained in the Telluride Land Use Code.
b. Pools, custom-built hot tubs, or factory-built portable spas shall also meet the Energy Mitigation Program requirements in Section 15-9-40.
c. Pools, custom-built hot tubs, or factory-built portable spas shall be equipped with a vapor-retardant pool cover on or at the water surface. Pools/spas capable of being heated above 90 degrees F must have a pool cover with a minimum insulation value of R-16.
(6) Garage door for heated garages shall have a value of R-18.
(7) Electrical resistance heating in living space is prohibited except for (a) the replacement of an existing system that is not subject to meeting the requirements of the Energy Code as provided in Subsection (c) of this Section; or (b) for heating small spaces less than one hundred (100) square feet.
(8) Mechanical Systems. Roofs shall be designed to not need electric underlayment mat heating unless approved by the Building Official and shall require temperature and moisture sensors.
(9) Snow- and ice-melting systems shall include automatic controls configured to shut off the system when the pavement temperature is above fifty (50) degrees F (ten (10) degrees C) and precipitation is not falling, and an automatic or manual control that is configured to shut off when the outdoor temperature is above forty (40) degrees F (four (4) degrees C). Electric resistance snow/ice melt systems are prohibited except for the heat tracing of gutters and associated downspouts. Snow/ice melt systems (except roof or gutter heat tracing) shall also meet the Energy Mitigation Program requirements in Section 15-9-40.
(10) Construction Waste. All sites shall have at least two (2) lockable bear-proof polycarts for (a) food items and (b) recyclables.

(11) Renewable Energy.One hundred percent (100%) of the building’s electricity use must be provided for with renewable energy, either produced on site or purchased through a Green Power Production Program. Creative alternative options will be considered by the Building Department. (Ord. 1502 §1, 2020)


Jump to Energy Conservation Code Hub for; the western slope of Colorado; Aspen, Telluride, Mountain Village, Town of Snowmass Village, Basalt, Carbondale, Pitkin and Eagle County…


Colorado Energy Conservation Code Hub

One stop for energy code information on the multiple jurisdictions of the Roaring Fork Valley, Telluride and Mountain Village.

I will try to keep this list current.


Jump to Aspen Colorado’s energy conservation code compliance page…

Pitkin County

Jump to Pitkin County’s energy conservation code compliance page…

Town of Snowmass Village

coming soon


Jump to Basalt Colorado’s energy conservation code compliance page…


Jump to Carbondale Colorado’s energy conservation code compliance page…

Eagle County

Jump to Eagle County Colorado’s energy conservation code compliance page…

Town of Telluride

Jump to Town of Telluride Colorado’s energy conservation code compliance page…

Mountain Village

Coming soon







Pitkin County, Colorado’s “The Matrix” energy code addendum

Pitkin County as has a new Energy Code Ordinance in effect as of July 22, 2020, Title 11 Section 11.32

Pitkin County, Climate Zone 7,  has added a residential energy conservation addendum for new construction and remodels, on top of the 2015 IECC requirements. Why? Basically, it is to bring construction in line with the Climate Action Plan. PitCo sponsored some fascinating research. One study says that about 70% of GHG (Green House Gas) emissions in Pitkin County are from the built environment. Another study predicts that more houses will be built in Pitkin County. Yet another study tracked the energy consumption of 900 houses for four years then, consumption was compared to house size. One might expect a 10,000 square foot house to have ten times the consumption of a 1,000 square foot house, but the study shows that the consumption of an average 10,000 square foot house was closer to thirty times the consumption of the 1,000 square foot house! How is this possible? It is because as the houses get bigger, they tend to get more luxurious. This means the house is more likely to be packed with energy-consuming amenities like; high percentages of glazing, large interior volumes, snowmelt, pools, hot tubs, saunas, conditioned wine cellars, conditioned garages, audio-visual-security systems, humidity control, air conditioning, multiple redundant appliances, steam showers, multiple redundant shower heads, heated toilet seats and towel bars and a plethora of other electric-powered gizmos.

The addendum has been come to be know as “The Matrix” because of the table format that outlays the requirements. There are two tiers of compliance; one for houses under 5,750 square feet and one for those over. The Matrix also makes a differentiation between houses that have more and less than 15% glazing. There are special requirements when working with existing construction, including; an energy assessment of the existing structure, air sealing improvements and occupant, crawlspace and attic ventilation compliant with current code.

New Construction

The HERS/ERI compliance information is found under the IECC adoption, in the REMP section, Appendix A.

What does this mean for the Architect?

  1. HERS of 60 before renewable energy is applied, HERS of 30 afterwards.
  2. Significant mandatory requirements; 50%-75% engineered lumber, insulated headers, 24” stud spacing, insulated corners or alternate construction, glazing U-factor of .28, ENERGY STAR appliances, mechanical commissioning of complex systems, sealed ductwork, garage exhaust fans, rough-in for PV and thermal solar and EV charging outlets.
  3. Any house with more than 15% of its walls glazed will be required to use the 2015 IECC UA trade-off (REScheck) or ERI compliance (HERS Rating) alternatives; no prescriptive submittals.
  4. Any house larger than 5,750 square feet will be required to use the 2015 IECC ERI compliance alternative; no UA trade-off or prescriptive submittals.
  5. Get in the habit of retaining an Energy Rater, early in the process.

Upgrades to existing homes

Remodels and small additions are standard, just meet the code with your new construction. Upgrades required when assemblies or systems are demoed in the course of work.

If your project is a larger addition, you will need a Projected HERS rating and an infiltration test on the house before you start to create a baseline, that must be surpassed by 15% at the final. The Projected HERS will help create a road map to the required Confirmed HERS rating of 58. Getting a existing house with a n addition to HERS 58 could be easy, or it could mean work on the existing portion and/or additional renewable energy production, depending on state of the existing house.


Link to PitCo Building & Energy Codes page where you can find the REMP calculator spreadsheet.

Confluence Architecture & Sustainability can help with REMP calculations and provide all the documentation, modeling, testing and certification required to navigate the Matrix.


Jump to Energy Conservation Code Hub for; the western slope of Colorado; Aspen, Telluride, Mountain Village, Town of Snowmass Village, Basalt, Carbondale, Pitkin and Eagle County…


Carbondale’s new Energy Code adoption

Beginning the 1st of July 2020, The Town of Carbondale revised their REBP (Residential Efficient Building Program). Carbondale is currently on the 2009 IRC (International Residential Code), the 2012 IgCC (International Green Construction Code) and the 2015 IECC (International Energy Conservation Code).


Link to REBP guidelines and REBP checklist here…

Carbondale has adopted the 2015 IECC and has a REBP (Residential Efficient Building Program). The chart below is the crux of understanding the energy code compliance.

What are the submittal requirements? Let me try and unpack what this chart means. Carbondale has made solar PV mandatory in almost all cases. The Building Official has unofficially made continuous wall insulation mandatory. Handicapping a HERS Rating this way, pretty much destroys the effectiveness of the tool. But against my strident protest, they followed CORE down this path. PV installers rejoice! Window salesmen- call your lawyer.

I think this lopsided push for PV is born out of COREs mission to electrify all houses. And why not PV? Because- the point of doing an energy model is to find the most cost-effective path to a set goal. If you declare PV the winner without a fight, you have cheated the science, tipped the scales. PV is pretty great, when would it really matter? When glazing becomes a large portion of the envelope load. When does that happen? Remodels obviously. The math might show that the old windows should really be replaced for reasons of heat loss, service life, comfort, etc. but, the project has already blown it’s wad on a PV system, got all the points they need, window replacement off the table. Another time glazing becomes overwhelmingly important- large areas of glazing facing south or west. I routinely see custom homes in River Valley Ranch with more than 30% glazing factor (30% of the above grade walls are made from glass). In these homes getting the right kind of glazing is huge. Sometimes the SHGC is more dominate than the U-factor! These southern view window walls are the only reason some of these houses require air conditioning. Also, a blind favoritism towards PV will stifle development/implementation of other kinds of renewable energy production, sorry GSHP, thermal solar and Drain Water Heat Recovery. Same argument for CI on the walls. The code does not make CI mandatory, I think, because flexibility is good, and CI can easily be traded off for better performance elsewhere. Ranch style houses typically have more roof area than walls area, why not make CI on the roof mandatory? It would move the needle more. And on the roof, you don’t even have all the technical problems with fenestration openings, siding and stone veneer attachment, etc. CI has many wonderful benefits, and I recommend it for most jobs, but it is rarely the first most cost-effective way to conserve energy. Ok, I’m getting off the soapbox, on with the submittal requirements…

I’m told the “percent better than code” row should be stricken from this chart; it no longer applies.

I’m told the “(option)” under the Tier 1 column means that a less than 2000 square foot house can submit using the prescriptive path as long as 1.5 watts per square foot of PV is provided. I don’t understand why, but they also require a Total UA Compliance calculation to be performed and submitted. No requirement to perform over basic compliance, so it just equal to prescriptive anyway. Or submit a Projected HERS rating of 50 in lieu, PV or not.

So basically what Carbondale is saying is that the prescriptive (402.1), the performance path (405) and ERI (406) are not a compliance option. Every single project will have to submit at least a Total UA Compliance Calculation (402.1.5), and PV design showing 1.5 watts per square foot or a HERS rating.

Currently, the Town is not considering ADUs (Accessory Dwelling Units) as their own unit. No need to include in REBP submittal, HERS rating or blower door infiltration test.

The required points refer to the REBP checklist (an Excel spreadsheet). Points are earned by including features in the house like, efficient framing, water conservation, chemical reduction, etc. Refer to the guidelines to understand how to fill out the checklist. Extra points are awarded for above code HERS (Home Energy Rating Score), infiltration rates and solar. Confluence can perform these tests and produce these compliance reports. Please call us early in the process so we can help you optimize the insulation and comply with the energy code in the most cost-effective way.


Carbondale is on the 2009 IBC (International Building Code), but they have also adopted the 2012 IgCC (International Energy Conservation Code).

Link to Carbondale’s heavily amended adoption of the IgCC here…

Navigating the IgCC is a deep subject, but expect it touch every phase of your project. The code requires above IECC insulation and infiltration mitigation, construction waste tracking and structured plumbing. The code requires third-party inspections and testing for the envelope. Confluence has been the code compliance and envelope consultant for six IgCC projects now. The Town of Snowmass Village has also adopted this code. Please calls us early in the process if you are planning a commercial project in The Town of Carbondale or The Town of Snowmass Village.

Jump to ICC’s overview of the International Green Construction Code…

Jump to Energy Conservation Code Hub for; the western slope of Colorado; Aspen, Telluride, Mountain Village, Town of Snowmass Village, Basalt, Carbondale, Pitkin and Eagle County…


Confluence turns 20!

April 1st 2020, Happy birthday Confluence Architecture and Sustainability.

Solar-powered inspections…

And Mark became a certified International Code Council certified Residential Energy Inspector/plans examiner and a IECC/HERS Compliance Specialist.