Technical: Comments to Proposed DOE Residential Boiler Rule
The Plumbing-Heating-Cooling Contractors–National Association (PHCC) supports appropriate installation of high efficiency products. PHCC is concerned with the proposed gas hot water boiler efficiency level of 85% and the proposed oil hot water efficiency level of 86% approaching the condensing threshold. At some operating conditions, condensation may be produced in either the boiler or the vent system degrading the useful life of the product. It would be advisable to have minimal increases (one percentage point) to these products to prevent installations with significant issues three to five years down the road.
PHCC has additional concerns with the concept of increasing efficiency by increasing heat exchanger surface area relative to an established firing rate. While this is a logical concept, not in fact new or revolutionary, it is constrained by market forces relative to the economic impact of this increase. The result will be an increase in product cost to the consumer. The installing contractor will be the person who has to explain these costs to the consumer, consumers who may already be facing unexpected repair expenses.
An added detriment to the approach of increased heat exchanger size would be an increase in standby losses due to the increased boiler mass. This increase could result in additional losses which would offset the operating efficiency gains. Some boiler types are more readily adaptable to increases, some types of boilers may simply reduce firing rate to achieve this gain. Either way products would have to have design modifications, new testing, and new ratings applied. Contractors will be faced with retraining their installation and sales forces to accommodate these changes, again all at the consumer’s expense.
Installation professionals currently evaluate heating jobs to select the equipment that best fits the needs of the consumer. Consumers have the right to select the product that best fits their needs, performs as advertised, and meets or exceeds its projected useful life.