Proven performance
No surprises. You’ll get exactly what you paid for, and we got it checked by an independent public lab. Read the test report from the Centre Scientifique et Technique du Bâtiment to see it yourself.
71 % efficiency : most performant WWHRS on the market
Obox is the most efficient Waste Water Heat Recovery System on the market. Thanks to high-end technology (5 patents), it gets you the most savings any passive WWHRS can. You can calculate how much savings for yourself here.
How was obox tested ?
The Centre Scientifique et Technique du Bâtiment designed a test protocol for all WWHRS to be sold on the french market. A 60 L shower is run at a 8 L/min flowrate. Cold water is 12.8 C, hot water is 55 °C and drain water is 37 °C.
Every second, heat power used by the shower (1) and recovered heat power (2) are recorded.
When temperatures are steady, efficiency can be computed : it is the ratio (3) between recovered heat power (2) and heat power used by the shower (1). Obox has a 71 % efficiency, i.e. it recovers 71 % of the heat that goes down the drain.
Before you can see this result on your energy bill, some heat losses must be accounted for – nothing obox can do about. Namely, heat is lost by evaporating water in the sowher cabin and though the pipes between the shower drain and obox. CSTB has measured this to be a 3 °C loss, i.e. 11 % of the total energy your shower uses in the first place doesn’t make it to obox. Hence, that’s a final (100 % - 11 %) x 71 % = 63 % overall yeld. This is the energy cut you will see on your hot water bill.
CSTB also measure how fast Obox gets to its 71 % efficiency : the lab computes a “transient coefficient” (4). It is written as the ratio between the actual recovered heat power over the whole shower length (t2-t1, i.e. 450 seconds), and the heat power that would have been recovered if obox had been “hot” (71 % efficiency) from the start. When Ctrans is 95 %, it means obox only lost 5 % before it was fully efficient.
