Last week’s forum activity was buzzing with thoughtful exchanges and technical debates. Members shared experiences about the challenges faced by new technicians when tackling large systems, and there was a lively debate on whether closing vents truly saves energy or if it’s merely a myth. Discussions on balancing empathy and efficiency during no-heat emergencies also drew significant attention. Additionally, several members delved into the history and origins of industry practices and superstitions, sparking curiosity and engagement.
This Week’s Hot Topics
Where new techs stumble on big systems
Experienced professionals are sharing insights on the common pitfalls that new technicians face with complex systems. It’s a must-read for those mentoring or just getting started. Read more here
Closing vents: energy saver or myth
This discussion tackles the age-old question of whether closing vents truly conserves energy. Opinions and experiences are varied and enlightening. Read more here
Balancing empathy and efficiency on no-heat days
Handling no-heat calls with both care and competence is a challenge. This thread explores strategies for maintaining professionalism and empathy. Read more here
Origin of the Friday startup superstition
Curious about why some avoid starting projects on Fridays? Dive into the origins of this superstition and share your thoughts. Read more here
Course recs for high‑MERV and duct design
Members are exchanging recommendations for courses focusing on high-MERV filtration and efficient ductwork design, a great resource for ongoing education. Read more here
Earliest heat pump used for salt works
A fascinating historical look at early heat pump applications in salt production, perfect for history buffs in the industry. Read more here
Origin of the 400 cfm/ton rule
Ever wondered where this rule of thumb comes from? This thread sheds light on its history and relevance today. Read more here
Why 15‑minute intervals in BAS
Learn why building automation systems commonly use 15-minute intervals and how it impacts operations. Read more here
ESP-to-CFM quick check for MERV 13
Get a quick guide on checking ESP to CFM for MERV 13 filters, a handy tip for field technicians. Read more here
Why we drill 1/4-inch test ports
This practical discussion covers the reasons and benefits of drilling 1/4-inch test ports, a common practice in the field. Read more here
Thank you for staying engaged with our community. Your contributions and curiosity are what keep these discussions rich and helpful. Looking forward to another week of shared learning.
I’ve only seen closing a couple registers help after measuring ESP and sealing leaky ducts — otherwise it’s like pinching a garden hose and just spiking pressure. Try this: verify external static stays under about 0.5 in. w.c., keep closures under about 10% of total supply area, and prioritize leaks/balance; DOE’s duct-sealing guide is solid: https://www.energy.gov/energysaver/duct-sealing. Would love to hear ESP and blower watt numbers before/after from anyone testing this.
Quick example: on ECM blowers I clamp the motor lead and, after closing one bedroom register for 2 minutes, compare amps to the board’s blower table; if amps climb and target CFM drops, that closure isn’t saving energy, so I reopen it or switch the fan profile to a low-static setting. Small caveat: on a zoned setup with proper relief it can help, but in the single-zone no-heat situations folks mentioned last week it mostly just raises watts and noise, @Marta.
Before anyone tries “closing vents,” I do a quick door-closed pressure check with a $40 digital manometer: tube under the bedroom door, shut the door, then shut that room’s register; if it jumps past about 3 Pa (0.012 in.w.c.), I reopen it… Did anyone else tie this back to last week’s debate on comfort during no-heat emergencies and unintended side effects. If you really need to throttle that room, a simple transfer grille or jumper keeps pressure in check and avoids wasted blower power.
If the bedrooms don’t have return paths, I’ve had better results adding a small transfer grille than telling folks to shut registers — cheaper than a zone panel and it calms the pressure. Quick check: watch temp rise (return-to-supply) while you crack a single register about 25% closed; if the rise jumps more than about 5°F, reopen it and consider a jump duct instead, @scobake.
When someone wants to shut a few, I clip a clamp meter on the blower lead and watch amps while I close one register at a time; if amps climb and the furnace “temp rise” creeps toward the nameplate max, it’s costing more than it saves. I’ll allow a slight crack on an oversized system for noise or drafts, but only if the temp rise stays in range, @Guide.
I’ve had better luck hunting return leaks before anyone starts closing supplies — smoke pencil around the air handler with the fan on; if it’s drawing attic or basement air, any ‘savings’ get eaten instantly. Closing vents is like squeezing a balloon, @Guide: the air just finds the leaks, so seal the return and, if the equipment allows, drop the blower to a lower CFM stage on mild days.