What Counts as an HVAC Emergency
What genuinely needs somebody out tonight, what can wait until morning, and what you should handle yourself before calling anyone.
Derek Mills ·
Derek Mills
Co-owner, service lead
Derek co-founded C&D Mechanical in 2022 and runs the service side. He is the one on the roof in February and under the crawlspace in August, which is where most of what he writes about comes from.
Articles by Derek Mills
Rust Stains and Grit in the Water: Iron and Sediment
Orange staining, black specks, and sand in the aerators are three different problems with three different fixes. A softener is not always the answer.
Derek Mills ·
Why Your Mini Split Smells Musty When It Turns On
That damp gym-bag smell has one common cause and one uncommon one. Neither of them is fixed by an air freshener.
Derek Mills ·
Spring AC Tune Up: What Is Worth Doing
What a real tune up includes, what you can do yourself in twenty minutes, and how to tell a genuine service from a sticker on the side of the unit.
Derek Mills ·
What Auxiliary Heat Means on Your Thermostat
Aux heat is normal in a cold snap and expensive if it runs all the time. How to tell which one you have.
Derek Mills ·
Your Heat Just Went Out. Do These Things First.
Six checks that solve a real share of no-heat calls, what to do about the house while you wait, and when to stop and call immediately.
Derek Mills ·
Why Your AC Coil Freezes Up
Ice on an air conditioner in July looks backwards and always means one of two things. How to thaw it safely and stop it recurring.
Derek Mills ·
Rooftop HVAC Units: What Neglect Actually Costs
RTUs are out of sight and they stay that way until the tenants complain. What a real quarterly service covers and the failures that come from skipping it.
Derek Mills ·
Mini Split Maintenance: What You Can Do Yourself
Ductless systems are low maintenance, not no maintenance. The filters you should be rinsing monthly and the deep clean that needs a tech.
Derek Mills ·
Why Is My Heat Pump Blowing Cold Air?
A heat pump that feels like it is blowing cool air is usually working fine. Here is how to tell the normal reasons from the ones worth a service call.
Derek Mills ·
Furnace Turning On and Off Every Few Minutes
Short cycling wears equipment out early and it is almost always one of five things. Two of them you can check without tools.
Derek Mills ·
Boiler Pressure: What the Gauge Should Read
Where the needle belongs on a residential boiler, what sends it too high or too low, and which of those you can safely deal with yourself.
Derek Mills ·
How to Bleed Air Out of a Hot Water Heating System
Air in the loop is one of the most common heating complaints and one of the few you can genuinely fix yourself. The order matters.
Derek Mills ·
What Those Noises From Your Water Heater Mean
Popping, rumbling, and a high whine are three different problems. One is nearly always sediment and one means shut it off now.
Derek Mills ·
Air Conditioning Not Cooling: What to Check Before You Call
Four things a homeowner can check in ten minutes, and the symptoms that mean you should stop and pick up the phone instead.
Derek Mills ·
Baseboard Heat Not Getting Hot? Work Through This First
One cold zone, one cold room, or the whole house cold are three different problems. Sorting out which one you have narrows it down fast.
Derek Mills ·
Preventing Frozen Pipes in a New Hampshire Winter
Which pipes actually freeze, what to do before the cold snap, and what to do in the first ten minutes if one already has.
Derek Mills ·
How Often Should You Really Change Your Furnace Filter?
The number on the box assumes a house that does not exist. What actually determines your interval, and why a thicker filter is not always better.
Derek Mills ·