Rachel H. from Wichita. I've got a 12-tenant office building where Westar installed the main meter with 400:1 CTs but each tenant sub-meter has different multipliers - some 50:1, some 100:1, some direct read. The main meter consumption doesn't match the sum of tenant meters. Westar says it's not their problem since the sub-meters are ours. The main meter Schedule GS-2 rate bills are about $8,000/month but tenant sub-meters only add up to about $5,500 worth of usage. Has anyone successfully gotten utility cooperation on sub-metering multiplier verification?
Multi-tenant building sub-metering multiplier nightmare
Greg L. in Atlanta. This is tricky because utilities typically only warrant their main meter, not customer-owned sub-meters. However, if your main meter multiplier is wrong, that's their issue. I'd start by having the main meter tested independently. If it's accurate, then your sub-meter multipliers or CT ratios are the problem. Georgia Power helped us audit a similar situation once we proved their main meter was right.
Randy Dawson here. Rachel, this is a common problem in multi-tenant buildings. The key is to establish a baseline - get the main meter tested first to verify the 400:1 multiplier is correct. Then audit each sub-meter CT ratio and multiplier separately. I've seen cases where sub-meter CTs were labeled wrong from the factory, or where electricians mixed up CT ratios during installation. Document everything with photos of nameplates and wiring. If there's a significant loss between main and sub-meters, you might also have load that's not sub-metered - common area lighting, HVAC equipment, etc.
Helen K. from Little Rock. Had this exact issue with Entergy Arkansas. Turned out three of our sub-meters had 200:1 CTs but were programmed as 100:1 multipliers. The building management company's electrician had misread the CT labels during install. Cost us about six months of wrong tenant billing before we figured it out. The utility was actually helpful once we proved their main meter was accurate.
Thanks everyone. We had an independent meter test done - the main 400:1 setup is accurate. Found the problem: two of the larger tenants have 100:1 CTs but someone programmed the sub-meters as direct read. Those two tenants were being billed at 1/100th of actual usage. Now I get to explain to them why their electric bills are about to go up 10x.
Duane K. from Bend OR. Ouch Rachel. That's going to be an uncomfortable conversation. Make sure you have documentation showing the error wasn't intentional and get everything in writing about the correction. Tenants sometimes think you're trying to scam them when bills suddenly jump like that.
Update: The two affected tenants are threatening legal action over the billing corrections. They don't want to pay back-bills even though we have clear documentation of the metering error. One tenant owes about $12,000 in under-billed amounts. This is why I hate sub-metering projects.
Norma H. from Knoxville. Rachel, check your lease agreements. Most commercial leases have clauses about utility billing errors and corrections. You might be able to recover some of the under-billed amounts, but it depends on your lease language and state law.
Karen W. in Charlotte. We had similar tenant pushback. Ended up settling for about 60% of the back-billing amount just to avoid legal costs. Document everything for future sub-metering projects - photos of every CT, every meter setting, everything. It's the only way to protect yourself when these errors happen.