In our LinkedIn group (https://linkedin/groups?home=&gid=8144595&trk=groups_item_detail-h-logo), someone asked a really great question: When doing inspections for HVAC is anyone having trouble locating the efficiency ratings for the furnace, HRV, and Water Heater? The furnace is usually pretty easy to get the efficiency rating for, but the HRV and Water Heater is a lot harder to find, especially out in the field. We have put together some slides and site photos on this topic. They can be found at: bowsertech/OBC2014/DHW-EF-HRV-SRE.pdf When looking at the document the first 5 pages are slides 97 through 105 from our training course earlier this year on the OBC 2014 changes. Page 6 is an HRV label from a Venmar 1.5 EKO. There are two efficiency ratings to look for, the first is for compliance to OBC 9.32.3.11.(2) where Sensible Recovery Efficiency (SRE) @ -25C must be at least 55% at an airflow of not less than 30 L/s. This would be the third line down in the Energy Performance section. The number is 64% @ -25C and 29 L/s. Although one could make the argument that it does actually comply with the language of the code, extrapolation says that if the flow was 30L/s efficiency would not fall to less than 55%. The other criteria is called out in sentence 2.1.1.1.(17) of SB12. The value needed is the SRE again, but this time at a test temperature of 0C and a flow equal to the principal exhaust flow but not more than 30L/s. For this unit, that would be 75% or 74% depending on the principal exhaust flow. For the purposes of OBC compliance Sensible Recovery Efficiency is the right value. Apparent Sensible Effectiveness is only used for Heat Loss & Gain Calculation or calculating delivered air temperate. I have a beef with Venmar about their labels and that is that the published model name is EKO 1.5 HRV, but the model name on the label is 43901. WRTO field documentation where we always take a picture of the rating plates, this is not helpful. The next picture is a label on an Aira RNC5-TPF. On this label, the SRE numbers are not actually printed although there are places where they should be. A full listing of all HVI-Certified HRVs and test results is available at: hvi.org/proddirectory/index.cfm The next two pages are of a water heater and the label. Unlike furnaces (which have labels so big you can check them by looking in a basement widow), the water heaters are very cagey about their EF ratings. The only clue that this one meets the 0.67 EF minimum is the E2 code at the end of the model code. Manufacturers literature will usually say, especially for higher efficiency units (see slide 101). There is an on-line listing of water heaters at oee.nrcan.gc.ca/pml-lmp/index.cfm?action=app.welcome-bienvenue (you have to scroll done to find them). In short, Both HRV manufacturers and especially water heater manufacturers can do a much better job of making their performance numbers easy to read by field inspectors.
Posted on: Wed, 13 Aug 2014 18:47:52 +0000
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