With the popularity of Nest and other IP-connected thermostats, real-time HVAC data collection is possible. This data can address and reduce several risks associated with residential retrofits from consumer, contractor, and policymaker perspectives. This talk will present pilot real-time HVAC data and discuss its potential benefits in residential retrofits. Data was collected from five homes in the Northeast for over six months. Thermal decay curves from "cold events" are able to characterize the thermal performance of the building. For the consumer, this provides an intuitive measure of the overall "thermal leakiness" of the house, which combines air leakage and thermal conduction losses. For the contractor, this enables a credible way to separate out the building from the behavior of the occupant and a way write performance guarantees. For the policy-maker, this pre-retrofit targeting and post-retrofit measurement and verification that is independent of the utility data, which could also enable pay-for-performance. Real-time HVAC data complements (but does not replace) traditional blower door and thermal camera methods. These measurements can be achieved at a per home cost, at scale, of approximately $40 for 2 years of monitoring plus other consumer benefits. I hypothesize that a low-cost measurement protocol, like real-time HVAC monitoring, is essential for widespread adoption of energy efficiency retrofits.