The Gree Winter Checklist: How to Choose a Dehumidifier and Prep a Side Discharge Heat Pump

Full confession: most of the mistakes in this checklist are mine. I've been handling commercial HVAC orders and installations for nine years, and I've documented 14—maybe 15 by now—real screw-ups that cost roughly $46,000. Or rather, $46,000 is what I tracked. The actual number is probably higher.

If you manage a small commercial building, a warehouse, or a light commercial space, this list is for you. It is not a full equipment spec. It's the practical stuff people forget, and it's the checklist I now make every technician follow before winter.

Six steps. No fluff.

1. How to choose a dehumidifier (the part most people get wrong)

It's tempting to think you can choose a dehumidifier by square footage alone. But the pint rating on the box is measured under a specific test condition, and the number changes depending on which standard the manufacturer uses. The current DOE test method rates capacity at 65°F and 60% RH. The older 80°F/60% RH rating gave higher numbers. So a 70-pint unit under the old test is not the same as a 70-pint unit under the current test. I do not mean the manufacturer is hiding anything—I mean the test conditions matter.

Read the label. Look for the AHAM DH-1 rating and check the conditions. Then think about the room:

• Measure the actual space you need to dry—square footage, ceiling height, open doors, and whether it's a sealed crawlspace or an open warehouse.
• If the drain isn't below a gravity line, buy a unit with a built-in condensate pump. Bucket overflow damage is usually worse than a dehumidifier failure.
• Check the filter access. If you have to take the whole unit apart to clean it, you won't clean it.

ASHRAE recommends keeping relative humidity between 30% and 60%. For a commercial basement or crawlspace, I usually aim for 50% and let the unit do the rest. I don't have hard data on brand failure rates, but the Gree dehumidifiers we put in client buildings have had fewer warranty calls than the budget units I bought for my own projects. That's my experience, not a lab test.

2. Check the low-ambient spec on your heat pump

If you have a Gree side discharge heat pump, the side-discharge design makes the coil easier to access than a traditional rooftop unit—but only if the unit is mounted with enough clearance. I've seen units tucked so close to a wall that the coil could barely breathe. Write the required clearance into your spec.

More important: don't assume a heat pump will heat all the way down to your design temperature. Check the manufacturer's low-ambient heating curve. Some inverter models provide rated output down to -15°C (5°F). Others start losing capacity at 35°F. The NEEP cold-climate heat pump specification is a useful benchmark here.

My most expensive mistake: I approved a quote for a heat pump installation without adding the low-ambient kit. The bid was $2,100 less, and it looked smart for one month. Then the unit started defrosting in cycles at 15°F, and the client was rightfully unhappy. The service call and retrofit added about $850 to the job, plus a week of cold calls and embarrassment.

• Confirm the low-ambient heating capacity in writing before you order.
• Check defrost settings and coil clearance on side-discharge models.
• If the quote says heat pump without cold-climate kit, ask what's included.

3. Winterize the Gree air cooler (or cover it correctly)

If you have a Gree air cooler in a warehouse or shop, winterizing it isn't optional. I skipped the drain step once. The water line froze, cracked the pump housing, and cost $320 to replace—plus a delay we didn't plan for.

The evaporative pads need to be dry before the unit sits all winter. A wet pad is a mold pad. Even if you're not using the space in cold months, cover the intake so dust and debris don't get pulled in.

• Drain the water tank and lines completely.
• Clean or replace the pads, then let the unit dry before covering it.
• Label the disconnect so nobody turns it on in February with a frozen line.

4. Check backup heat before you need it

The backup heater never gets used until it's needed. That's the problem. Every year, I get a call in January from a facility manager who discovered that the Mr. Heater units in the warehouse don't work—or worse, don't get turned on because they're behind a stack of pallets.

If your backup heat is portable, check it before December. That means inspecting propane hoses for cracks, testing the igniter, and verifying the carbon monoxide detector is working. It also means actually starting the unit for five minutes. A heater that worked fine in March won't help at 2 a.m. in January.

One of the more embarrassing moments on my list: we ordered 60 Mr. Heater units for field offices, and the client installed them without checking the hoses. We caught one cracked hose during a routine inspection. That was close.

Checklist: hoses, igniter, batteries, CO detector, and a clear path to the units.

5. Don't forget the snow blower (it affects HVAC access)

This is the non-HVAC step that changes HVAC outcomes. If a service technician can't reach the rooftop unit because the walkway is buried, the visit becomes a cancellation and a rescheduling fee. In that category, the EGO snow blower is the one I see sitting dead in garages.

If you have an EGO snow blower, charge the battery and run it for five minutes before the first winter storm. I know that sounds too simple. But I've had to reschedule two service calls because the snowblower battery was dead and nobody knew it until the snow was already there.

Battery voltage drops in cold weather. A battery that was fine in October can read full at room temperature and die halfway through the first pass in January. If your model has a storage mode or charge limit, read that too.

6. Ask what's not included before you sign the quote

I've learned to ask 'what's NOT included' before 'what's the price.' The vendor who lists all fees upfront—even if the total looks higher—usually costs less in the end. The low quote that doesn't mention the low-ambient kit, the concrete pad, the disconnect, or the after-hours permit isn't actually low.

This isn't a criticism of any one supplier. It's the pattern I've seen across my documented mistakes. On one job, the equipment price was $14,000. The final invoice, with accessories and commissioning, was $16,200. The client approved the $14,000 number. The $16,200 was a relationship problem.

The vendor who lists all fees upfront—even if the total looks higher—usually costs less in the end.

So when you're comparing quotes for a heat pump or dehumidifier, ask for the line items. What's included in that number? What's excluded? What happens if the site condition changes? If they can't answer in writing, that's an answer.

Final notes: the mistakes I still see

Most of these issues are preventable. But they're only preventable if someone writes the checklist down. The common ones:

• Choosing a dehumidifier based on square footage instead of the AHAM/DOE rating.
• Assuming a heat pump's label means it will heat at low ambient.
• Storing an air cooler with water still in the pump.
• Letting backup heaters and snow blowers sit for eight months without a check.
• Signing a quote without asking what's not included.

I don't have hard data on how many contractors skip these steps. But based on the service calls I've seen, it's more than zero, and it's usually the same people every year. This checklist won't make winter fun. It will make it less expensive.