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ERV/HRV Sensible Energy Recovery Calculator

Calculate the sensible heat energy recovered by an energy/heat recovery ventilator, based on its rated sensible recovery effectiveness.

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Imperial · sales tax
The ERV/HRV's rated or design supply airflow.

This is the airflow through the energy recovery core — use the unit's rated airflow at the design operating point.

The temperature difference between the outdoor and indoor (or exhaust) airstreams entering the unit.

This is the available sensible temperature difference the recovery core can act on before applying the Sensible Recovery Effectiveness.

The fraction of the available sensible energy difference the unit actually transfers between airstreams.

This is the AHRI 1060-certified Sensible Recovery Effectiveness (SRE) published for the specific unit model at a stated test condition.

Recovered sensible energy

15,100 BTU/hr

Medium confidence

Use the specific ERV/HRV unit's AHRI 1060-certified Sensible Recovery Effectiveness rating at conditions close to your design case — SRE varies with airflow and temperature/humidity conditions, so a single manufacturer-published number applied outside its rated conditions is an approximation.

Then change the inputs to see how far the answer moves.

Show calculation logic

How this was calculated

Formula source(s)

  • Recovered sensible energy (BTU/hr) = 1.08 × Airflow (CFM) × Temperature Difference (°F) × Sensible Recovery Effectiveness (%), extending the standard ASHRAE sensible heat formula with the unit's AHRI 1060-certified Sensible Recovery Effectiveness (SRE) rating, which represents the fraction of available sensible energy difference the unit actually transfers between airstreams.

Inputs used

Airflow
500 CFM
Outdoor-to-Indoor Temperature Difference
40 °F
Sensible Recovery Effectiveness (%, per AHRI 1060 Rating)
70
Final result15,118.49 BTU/hr

Confidence note: Use the specific ERV/HRV unit's AHRI 1060-certified Sensible Recovery Effectiveness rating at conditions close to your design case — SRE varies with airflow and temperature/humidity conditions, so a single manufacturer-published number applied outside its rated conditions is an approximation.

What this calculation does not cover

  • Sensible heat only, which on an ERV is half the story. Moisture moved across the core is counted by a separate latent effectiveness, and in a humid climate that latent recovery can carry as much energy as this figure does — comparing an ERV against an HRV on this number alone hides the very thing that separates them.
  • This is gross recovery at one instant, not what the unit saves. Both fans run continuously against the core's pressure drop and that parasitic power comes straight off the benefit, while in cold weather the defrost cycle interrupts recovery for a share of exactly the hours it is wanted. A payback worked from this figure is optimistic on both counts.
  • Assumes supply and exhaust flows are equal, because that is the condition the effectiveness was certified at. Unequal duct runs, a loaded filter or an exhaust-dominant house shift the flows apart, so the unit recovers something other than its rating and pushes the imbalance into air moving through the building fabric instead.

Add the equipment this sizes

This result is a specification — 15,100 BTU/hr — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.

Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.1.1

Regulatory standards & verification citations1
  1. Recovered sensible energy (BTU/hr) = 1.08 × Airflow (CFM) × Temperature Difference (°F) × Sensible Recovery Effectiveness (%), extending the standard ASHRAE sensible heat formula with the unit's AHRI 1060-certified Sensible Recovery Effectiveness (SRE) rating, which represents the fraction of available sensible energy difference the unit actually transfers between airstreams.
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Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Now that you have the number

These guides cover the work this quantity is for — the first ones run this calculator inside the section that raises the question.

Called something else where you work? Ventilation with heat recovery — the term in each market, how close the equivalence really is, and the standard that governs it.

How to calculate ERV/HRV sensible energy recovery in 4 steps

  1. AirflowThe ERV/HRV's rated or design supply airflow.
  2. Outdoor-to-Indoor Temperature DifferenceThe temperature difference between the outdoor and indoor (or exhaust) airstreams entering the unit.
  3. Sensible Recovery Effectiveness (%, per AHRI 1060 Rating)The fraction of the available sensible energy difference the unit actually transfers between airstreams.
  4. Recovered sensible energyThe tool computes the recovered sensible energy from those figures and shows the formula, its sources, and a confidence rating alongside it.

Recovered sensible energy by airflow

Page defaults, not your figures above.

AirflowRecovered sensible energy (BTU/hr)
200 CFM6,047
400 CFM12,095
600 CFM18,142
800 CFM24,190
1,000 CFM30,237

Frequently asked questions

What does the Sensible Recovery Effectiveness (SRE) represent?
SRE is the fraction of the available sensible temperature difference between the outdoor and indoor/exhaust airstreams that the ERV/HRV core actually transfers, as certified under AHRI 1060 testing — a higher SRE means the unit recovers a larger share of that available energy.
Where does the 1.08 constant in this formula come from?
1.08 is the standard ASHRAE sensible heat factor for standard air (accounting for air density and specific heat), used to convert CFM × °F into BTU/hr — the same constant used in general sensible heat load calculations, extended here by the unit's SRE rating.
Is a single published SRE value accurate at all operating conditions?
No — SRE varies with airflow rate and the entering temperature/humidity conditions of both airstreams, so a manufacturer's published SRE at its AHRI 1060 rating point is an approximation when applied outside that rated condition. Use the SRE value closest to your actual design airflow and temperature difference for the most accurate estimate.
Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — a confirmed fix gets a permanent check of its own, so the same mistake cannot come back.