--- title: "Site vs source EUI before an HVAC assessment" description: "Choose the energy measure, units, floor area, and reporting year before an HVAC assessment. Use a synthetic example and questions for the owner." canonical: "https://scalewithsearch.com/articles/site-source-eui-hvac-building-assessment" --- ## Site navigation - [Scale With Search](https://scalewithsearch.com/) - Services - Services - [AI systems](https://scalewithsearch.com/ai-systems) - [Site build](https://scalewithsearch.com/work#site-build) - [Whole website fix](https://scalewithsearch.com/work#whole-website-fix) - [Content library with SEO](https://scalewithsearch.com/work#content-library) - [Working session](https://scalewithsearch.com/audit) - Start here - [Send your brief](https://scalewithsearch.com/work#send-your-brief) - [Example scope](https://scalewithsearch.com/work#review-the-example-scope) - [Prices and terms](https://scalewithsearch.com/work#prices-and-terms) - Industries - Real estate - [Real estate agents and teams](https://scalewithsearch.com/for/real-estate) - [Platforms, ownership, and IDX](https://scalewithsearch.com/for/real-estate/real-estate-website-platforms-ownership-idx) - [Search, content, and AI](https://scalewithsearch.com/for/real-estate/real-estate-search-content-ai) - [Inquiries, campaigns, and handoffs](https://scalewithsearch.com/for/real-estate/real-estate-website-inquiries-campaigns-handoffs) - [Buyer, seller, and local pages](https://scalewithsearch.com/for/real-estate/real-estate-buyer-seller-local-resources) - [Rules, privacy, and trust](https://scalewithsearch.com/for/real-estate/real-estate-website-rules-privacy-trust) - Browse by business - [Trades and home services](https://scalewithsearch.com/for/#group-trades) - [Health, wellness, and animal care](https://scalewithsearch.com/for/#group-practices) - [Law, finance, and IT](https://scalewithsearch.com/for/#group-professional) - [Marketing and SEO agencies](https://scalewithsearch.com/for/#group-agencies) - [Shops and manufacturers](https://scalewithsearch.com/for/#group-manufacturing) - [Restaurants, shops, studios, and nonprofits](https://scalewithsearch.com/for/#group-local-services) - Chiropractic practices - [Chiropractic and wellness practices](https://scalewithsearch.com/for/chiropractic-and-wellness-practices) - [Chiropractic and physical therapy clinics](https://scalewithsearch.com/for/chiropractic-and-physical-therapy-clinics) - [All industries](https://scalewithsearch.com/for/) - Resources - Free tools - [AI readiness check](https://scalewithsearch.com/check) - [Free tools](https://scalewithsearch.com/tools/) - [Free Starter Kit](https://scalewithsearch.com/kit/business-memory-starter-kit.zip) - Guides - [AI-native library](https://scalewithsearch.com/ai-native) - [Industry intelligence](https://scalewithsearch.com/intelligence) - [Office job guides](https://scalewithsearch.com/guides/) - [Business memory](https://scalewithsearch.com/articles/business-memory-for-ai-agents-guide) - [Agent governance](https://scalewithsearch.com/articles/ai-agent-governance-guide-small-business) - [Migration and ownership](https://scalewithsearch.com/articles/leaving-vendor-ai-memory-guide) - Articles - [All articles](https://scalewithsearch.com/articles/) - [What changed](https://scalewithsearch.com/changes/) - About - Evidence - [Proof](https://scalewithsearch.com/proof) - Scale With Search - [About](https://scalewithsearch.com/about) - [How it works](https://scalewithsearch.com/how-it-works) # Site and source EUI: read building energy data before an HVAC assessment Before discussing a building's energy intensity, name exactly what the number measures. An estimator needs the measure, units, reporting year, weather treatment, and property boundary together. A number copied without those labels is an unfinished observation. This guide helps commercial HVAC teams prepare that observation for an owner conversation. It does not identify faulty equipment or estimate replacement savings. The useful result is a question that an estimator can explain and a facilities manager can help resolve. The [HVAC contractor overview](/for/hvac-contractors) covers office records and approvals. The [commercial building intelligence guide](/intelligence/hvac-contractors) describes a broader research queue. Start here when that queue contains energy figures whose meaning needs clarification. ## Separate the building's use from the energy supply chain Site energy describes energy consumed at the property, reflected in utility bills. Source energy includes the raw energy needed upstream, including production and delivery losses. EPA explains this distinction in its [source and site energy guide](https://www.energystar.gov/buildings/benchmark/understand-metrics/source-site-difference). Use site energy when describing the reported consumption at the property boundary. Use source energy when the chosen comparison calls for the wider energy boundary. Keep the original measure visible whenever a figure enters a worksheet, email draft, or meeting note. EPA recommends source energy for comparisons across buildings, because site energy does not account equally for different fuel mixes. Its [source energy technical reference](https://portfoliomanager.energystar.gov/pdf/reference/Source%20Energy.pdf) explains this limit. The site-only examples below compare reported consumption intensity. They do not establish equivalent energy efficiency across different heating fuels. Do not replace a source EUI label with the shorter word “usage.” That change hides the boundary. Similarly, do not describe a source value as a quantity taken directly from a building's electricity bill. Ask which fuels and meters the underlying property record includes before discussing its significance. EPA uses national source-site ratios in Portfolio Manager. Its [source energy methodology](https://www.energystar.gov/buildings/tools-and-resources/portfolio-manager-technical-reference-source-energy) explains the underlying distinction. Do not invent a local conversion factor from a utility's marketing page or divide two unrelated published figures to create one. For the owner conversation, try this wording: “We have a reported whole-property energy measure. First, we want to confirm its scope and period.” That statement leaves room for corrections before anyone discusses mechanical work. ## Read EUI as a ratio with a time period Energy use intensity divides annual energy use by floor area. EPA describes the calculation and available measures in its [EUI definition](https://www.energystar.gov/buildings/benchmark/understand-metrics/what-eui). Keep the area definition beside the energy boundary when reviewing a reported value. In this guide, example EUI values use kBtu per square foot per year. The symbol kBtu means thousands of British thermal units. An annual total in kBtu and an annual intensity in kBtu per square foot answer different questions. Do not place them in the same ranking column. Consider a synthetic property with annual site energy use of 4,000,000 kBtu across 50,000 square feet. Its calculated site EUI is 80 kBtu per square foot for that year. This arithmetic illustrates the ratio. It is not a Seattle observation or an acceptable target for an actual property. Now imagine that somebody substitutes 40,000 square feet while preserving the same annual energy total. The ratio becomes 100. The changed result comes entirely from the denominator. Before treating a difference as an operating problem, ask whether the underlying property boundaries agree. When reading an existing published EUI, preserve it as reported. If you calculate another ratio, label it separately and explain its inputs. Do not silently overwrite the published figure with a calculation that uses a different area field. ## Confirm which floor area the record describes Seattle distinguishes confirmed building area, parking area, and self-reported area. Its [dataset field definitions](https://data.seattle.gov/api/views/teqw-tu6e.json) describe `PropertyGFABuildings` as building floor space excluding parking. `PropertyGFATotal` includes building and parking area. Separate self-reported fields also exist. For a size screen, record the chosen field's exact name. A label such as “about fifty thousand feet” is insufficient when another reviewer must reproduce the selection. Ask whether the reported property includes an adjoining structure, shared space, or a separately managed portion. Do not assume the area used in your local size band reconstructs the denominator behind a published EUI. Preserve the published intensity and its definition. Treat a discrepancy between area records as a question for the responsible property reviewer. Ask the owner which spaces are included in the energy accounts under discussion. Request clarification through the company's approved document process. Keep bills and other private records out of public research notes. The estimator needs the approved scope, not unrestricted access to the owner's files. If the owner corrects an area assumption, record the original value, corrected value, evidence, date, and responsible reviewer. A corrected building boundary should remain visible in later conversations about that property. ## Keep weather-normalized and unadjusted values separate Weather normalization estimates energy under average weather conditions. It does not remove every operating difference between properties. EPA's [climate and weather reference](https://www.energystar.gov/buildings/tools-and-resources/portfolio-manager-technical-reference-climate-and-weather) distinguishes weather normalization from adjustment across different climates. The [September 2025 technical reference](https://portfoliomanager.energystar.gov/pdf/reference/Climate%20and%20Weather.pdf) explains that weather normalization supports comparisons of one building over time. It does not adjust for differences between locations with different average climates. A normalized label alone cannot make those locations comparable. Seattle publishes separate fields for site EUI, weather-normalized site EUI, source EUI, and weather-normalized source EUI. Its [field definitions](https://data.seattle.gov/api/views/teqw-tu6e.json) identify the weather-normalized values as estimates under thirty-year average weather conditions. Choose the weather treatment before selecting rows for a comparison. If you choose unadjusted site EUI, keep every ranked row on that measure. If a normalized value is unavailable, mark it unavailable. Substituting an unadjusted value would change what the column means. For owner discussions, put both available values in separate labeled fields when that distinction matters. Ask what the reporting year represents operationally. Do not read the difference between the two measures as the saving available from new equipment. A normalization label also does not establish that two buildings operate alike. Continue asking about the property boundary and actual use. The [peer-group guide](/articles/hvac-building-energy-peer-group-comparison) explains how to decide which properties belong in the comparison. ## Work through a synthetic comparison before using a real one The following figures are invented for explanation. They describe three imaginary observations for the same calendar year. They carry no local benchmark, conversion recommendation, or equipment conclusion. | Synthetic observation | Measure | Annual EUI, kBtu per square foot | Interpretation before review | | --- | --- | --- | --- | | Building A | Unadjusted site | 80 | Candidate for a site-only comparison | | Building B | Unadjusted source | 150 | Different energy boundary; hold apart | | Building C | Weather-normalized site | 75 | Different weather treatment; hold apart | Sorting 75, 80, and 150 would produce a numerical order. It would not produce a valid comparison on one defined measure. The labels must control the decision before the arithmetic begins. Suppose the analyst later obtains Building B's unadjusted site EUI of 70. Building B can now enter a site-only discussion, subject to the remaining property checks. Its source EUI of 150 remains a separate observation. Neither value invalidates the other because they describe different boundaries. Suppose Building C has no unadjusted site figure in the available extract. Keep it outside this comparison. Explain why it was excluded. Do not estimate its missing value by borrowing the difference between Building A's two measures. The estimator's conclusion should stay narrow: “We can compare these labeled observations after confirming property use and scope.” It should not become “Building A needs replacement equipment.” That technical conclusion requires evidence this table does not contain. ## Put the observation year beside the access date Seattle defines `DataYear` as the calendar year represented by each record. The [Seattle metadata](https://data.seattle.gov/api/views/teqw-tu6e.json) supplies that definition. Record the reporting year independently from the date you accessed the dataset. For example, a synthetic worksheet accessed in October 2026 might describe calendar year 2024. The access date documents retrieval. It does not establish the building's equipment or operation in October 2026. Ask whether the owner knows of changes after the reporting period. Record the date and scope of any confirmed change. Keep an unconfirmed statement as an unresolved question until the responsible person checks it. When comparing two years for one property, preserve a separate observation for each year. Do not blend an older energy value with a newer area value without labeling the calculation. Review changes in reported boundaries before describing a trend. A current conversation can use an older observation if its age is clear. The estimator decides whether it still supports useful questions. If the owner needs a current assessment, leave that requirement explicit rather than making the public record appear newer. ## Bring a short assessment worksheet Use this proposed worksheet to prepare a discussion. It is an editorial aid, not an EPA form or a technical assessment standard. | Worksheet item | What to bring | Question to resolve | | --- | --- | --- | | Property identity | Public identifier and reported boundary | Is this the property under discussion? | | Energy measure | Exact field and units | Are we discussing site or source energy? | | Weather treatment | Normalized or unadjusted label | Are all compared observations using this treatment? | | Floor area | Field name and source | Which spaces belong to this record? | | Period | Observation year and access date | What changed afterward? | | Decision owner | Estimator and technical reviewer | Who can authorize the next assessment step? | Write questions in language the owner can correct. Ask “Does this record include the separately operated space?” rather than asserting that it does. Ask “Which recent assessment should we read?” rather than assuming that no assessment exists. Leave an explicit place for “unknown.” A blank cell can disappear during editing or look like a negative answer. A named unresolved fact gives the next reviewer a clear task without implying equipment condition. Close the conversation by recording the agreed next step and its owner. Keep technical scope, pricing, scheduling, and any work recommendation with the authorized people. The energy observation remains supporting context throughout that decision. ## Keep the explanation with the building history Store the accepted metric label, source link, reporting year, and reviewer correction together. Preserve why an observation was held apart. A later reader should understand the decision without reconstructing an earlier meeting. The [business memory guide](/articles/business-memory-for-ai-agents-guide) explains how retained decisions can support later work. For a public example, read the labels and limitations in [Building energy comparison](/tools/building-energy-comparison). Neither replaces the estimator's review of the actual property. Scale With Search can scope a building research process around the measures and decisions your team agrees to use. Bring one example observation and the person responsible for checking it. [Request a written scope](/work) Source note: EPA EUI, source/site, source energy methodology, and climate/weather pages and linked technical PDFs were reopened on 2026.10.28. Seattle metadata was retrieved directly that day after the web reader failed. The source energy landing page displays 2023-08-28, and its PDF is dated August 2023. The climate/weather landing page displays 2021-02-19, but its linked PDF is dated September 2025. Access dates do not update those documents. No live building values were used. All worksheets and synthetic figures above are editorial examples. Continue the website review: [AI-native HVAC contractors: the first functions to build](/articles/ai-native-hvac-contractors-first-functions); [HVAC After-Hours Website: What Does 24/7 Mean?](/articles/hvac-after-hours-website-availability); [HVAC contractor AI rules: data, approvals, and spend](/articles/hvac-ai-rules-data-approvals-spend); [HVAC building comparisons: choose a peer group and explain its limits](/articles/hvac-building-energy-peer-group-comparison); [HVAC Financing Pages: Check the Advertised Terms](/articles/hvac-financing-website-advertising-review); [Heat Pump Website Claims: Ratings and Bill Savings](/articles/hvac-heat-pump-efficiency-website-claims); [HVAC Project Pages: Show the Work Without Guessing](/articles/hvac-installation-project-pages); [HVAC Maintenance Plan Pages: Explain What Is Included](/articles/hvac-maintenance-plan-website-page); [HVAC marketing: connect your website and local profile](/articles/hvac-marketing-website-local-plan); [HVAC Refrigerant Copy: Remove Blanket Replacement Claims](/articles/hvac-refrigerant-website-copy-update); [HVAC Service Pages: Separate Repair and Installation](/articles/hvac-repair-installation-service-pages); [HVAC Search Console Report: Clicks and Inquiries](/articles/hvac-search-console-inquiry-report); [HVAC Warranty Pages: Separate Equipment and Labor](/articles/hvac-warranty-website-manufacturer-labor); [HVAC Websites in AI Answers: Fix the Source Facts](/articles/hvac-website-facts-ai-search-answers); [HVAC Website Credentials: Licenses and Certifications](/articles/hvac-website-licenses-certifications). [HVAC contractors](/for/hvac-contractors): website and search resources. ## Related: HVAC contractors - [AI-native HVAC contractors: the first functions to build](/articles/ai-native-hvac-contractors-first-functions) - [HVAC After-Hours Website: What Does 24/7 Mean?](/articles/hvac-after-hours-website-availability) - [HVAC contractor AI rules: data, approvals, and spend](/articles/hvac-ai-rules-data-approvals-spend) ---- ```text .|########||. .|########||. .|########||. |##||. .||##|. |##||. .||##|. |##||. .||##|. |#|. .|#|. |#|. .|#|. |#|. .|#|. |#| |#| |#| |#| |#| |#| .#| |#. .#| |#. .#| |#. .#. .#| .#. .#| .#. .#| |#. .#| |#. .#| |#. .#| |# ...... #| |# ...... #| |# ...... #| .# ||#########| #| .# ||#########| #| .# ||#########| #| .#. |######||######|. .#. .#. |######||######|. .#. .#. |######||######|. .#. #. .##|###|##|#|######| .# #. .##|###|##|#|######| .# #. .##|###|##|#|######| .# || |##|#||||||||||||#||#| || || |##|#||||||||||||#||#| || || |##|#||||||||||||#||#| || # |#||||||||||||||||||||#| #. # |#||||||||||||||||||||#| #. # |#||||||||||||||||||||#| #. || |#||||||||||||||||||||||#| || || |#||||||||||||||||||||||#| || || |#||||||||||||||||||||||#| || # .#||||||||||||||||||||||||#| # # .#||||||||||||||||||||||||#| # # .#||||||||||||||||||||||||#| # || ....|||#||||||##|#|||#|#||##||||....|. || || ....|||#||||||##|#|||#|#||##||||....|. || || ....|||#||||||##|#|||#|#||##||||....|. || #. . ....|# ....#||| ||| .#||| ....#. .# #. . ....|# ....#||| ||| .#||| ....#. .# #. . ....|# ....#||| ||| .#||| ....#. .# # . ||||#| .#####|| . .#| .#||| ||||# #. # . ||||#| .#####|| . .#| .#||| ||||# #. # . ||||#| .#####|| . .#| .#||| ||||# #. .| ||||| #. |#|||||. || #. |#||. .||||| || .| ||||| #. |#|||||. || #. |#||. .||||| || .| ||||| #. |#|||||. || #. |#||. .||||| || || |.... #. ....|#. |. ...|. ....|| || || |.... #. ....|#. |. ...|. ....|| || || |.... #. ....|#. |. ...|. ....|| || #. .||||||##||||||##||####|||||||#||||||#| .# #. .||||||##||||||##||####|||||||#||||||#| .# #. .||||||##||||||##||####|||||||#||||||#| .# # .||####|###########################|. # # .||####|###########################|. # # .||####|###########################|. # # .#||||||.#.|| # |. ..# #| #|||||#| # # .#||||||.#.|| # |. ..# #| #|||||#| # # .#||||||.#.|| # |. ..# #| #|||||#| # # .#|||||| .. |# ## |#| ...#|#|||#| # # .#|||||| .. |# ## |#| ...#|#|||#| # # .#|||||| .. |# ## |#| ...#|#|||#| # # .#|||#|# .# .#| #| ##|.#..#|||||#| # # .#|||#|# .# .#| #| ##|.#..#|||||#| # # .#|||#|# .# .#| #| ##|.#..#|||||#| # # .#||||||############|######|||||#| # # .#||||||############|######|||||#| # # .#||||||############|######|||||#| # # |...||#||||||#||||#|#||||||#|||||#||| |.| # # |...||#||||||#||||#|#||||||#|||||#||| |.| # # |...||#||||||#||||#|#||||||#|||||#||| |.| # #. .. ||||# .|||##|. |#| .|| || .|||#. #| # .# #. .. ||||# .|||##|. |#| .|| || .|||#. #| # .# #. .. ||||# .|||##|. |#| .|| || .|||#. #| # .# || | ...|| ...##| | #| .|. |. ##### .. .| || || | ...|| ...##| | #| .|. |. ##### .. .| || || | ...|| ...##| | #| .|. |. ##### .. .| || || ||||| || ||||#| . |. |. |#. ||||| |#| || || || ||||| || ||||#| . |. |. |#. ||||| |#| || || || ||||| || ||||#| . |. |. |#. ||||| |#| || || .# |.....#|....|#.||||.|||##.|#|....||.#||.#. #. .# |.....#|....|#.||||.|||##.|#|....||.#||.#. #. .# |.....#|....|#.||||.|||##.|#|....||.#||.#. #. #.|||||||#############################| ||| .# #.|||||||#############################| ||| .# #.|||||||#############################| ||| .# || ##||#||#||||||#||#||#||#||##. || || ##||#||#||||||#||#||#||#||##. || || ##||#||#||||||#||#||#||#||##. || # .#|||||||||#||#|||||||||||#| # # .#|||||||||#||#|||||||||||#| # # .#|||||||||#||#|||||||||||#| # || |#||||||||||||||||||||||#| || || |#||||||||||||||||||||||#| || || |#||||||||||||||||||||||#| || .# |#||||||||||||||||||||#| #. .# |#||||||||||||||||||||#| #. .# |#||||||||||||||||||||#| #. || |#||||||||||||||||||#| || || |#||||||||||||||||||#| || || |#||||||||||||||||||#| || #. .######|#|#########| .# #. .######|#|#########| .# #. .######|#|#########| .# .#. |#####||||#####| .#. .#. |#####||||#####| .#. .#. |#####||||#####| .#. |# ||########|| #. |# ||########|| #. |# ||########|| #. |# ...... #| |# ...... #| |# ...... #| |#. .#| |#. .#| |#. .#| |#. .#. |#. .#. |#. .#. .#| |#. .#| |#. .#| |#. |#| |#| |#| |#| |#| |#| .|#|. .|#|. .|#|. .|#|. .|#|. .|#|. |##||. .||##| |##||. .||##| |##||. .||##| .||########||. .||########||. .||########||. 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