Preserving Asset Value: The Property Manager´s Guide to Heating Vacant Buildings

By Porta Air Team Greater Chicago Area — Winter 2025

For property managers in the Chicago suburbs, winter brings a recurring and stressful dilemma. You are managing a vacant commercial property that is currently on the market. Suddenly, the primary rooftop unit (RTU) or boiler fails. Faced with a repair bill totaling thousands of dollars for a building that is intended to be sold, many owners are reluctant to invest in permanent fixes.

However, doing nothing is not an option. Without heat, a vacant building quickly becomes a liability. Frozen and burst pipes can lead to catastrophic water damage, mold growth, and a significant decrease in the property´s appraisal value. This is where temporary electric heating becomes the most strategic tool in a property manager´s arsenal.

The "Hold for Sale" Strategy

The most common application we see every winter involves buildings in transition. Property managers need to maintain a "dry-pipe" or "low-heat" state—typically keeping the interior between 50°F and 55°F—to ensure the plumbing and fire sprinkler systems remain functional without the expense of a full HVAC overhaul.

Electric heaters are the preferred solution for these vacant spaces for several key reasons:

• · No Fuel Logistics: Unlike propane or diesel fired units, electric heaters do not require fuel deliveries or tank monitoring, which is ideal for buildings that aren´t staffed daily.
• · Security and Safety: When using indirect-fired natural gas heater rentals, venting penetrations in outer walls may present a security risk. Daily monitoring of this equipment is mandatory to manage safety concerns.
• · Zero Emissions: Electric heat is 100% clean. There is no risk of carbon monoxide buildup or moisture accumulation, making it safe for long-term, unattended use in closed environments.
• · Dry Heat: Electric units provide a very dry heat, which helps pull residual moisture out of the air, further protecting the building´s interior finishes.

Versatile Solutions for Every Space

At Porta Air, we specialize in tailoring the heat source to the building´s specific electrical capacity.

1. Portable Electric Blowers

For smaller offices or retail "white boxes," we deploy high-velocity electric fan heaters. These units, often running on 208V or 240V single-phase or three-phase power, are designed to circulate air through large open areas. By placing them in central hallways, we create a thermal "heart" for the building that radiates warmth into adjacent rooms.

2. Strategic "Cold Spot" Management

In larger vacant complexes, we often find that the "core" of the building stays relatively stable, but the perimeter—near loading docks or glass-heavy entryways—is at risk. Our team can install a network of smaller electric units to provide targeted protection where it’s needed most.

Why Call Porta Air?

When a building´s heat goes down, time is of the essence. You need a partner who understands the balance between budget constraints and asset protection. Porta Air provides a full spectrum of rescue heating:

• · Electric Solutions: For clean, unattended, and simple operation.
• · Direct-Fired Solutions: For rapid thaws in unfinished or high-ventilation areas.
• · Indirect-Fired Solutions: For high-capacity, fume-free heat delivered through existing ductwork. Ie: similar to your permanent forced air heating system.

Don´t let a failed heating unit freeze your real estate deal. We can help you maintain your building’s integrity while it sits on the market, ensuring that the only thing "frozen" is the asking price—not the pipes.

*******To provide an accurate rental quote for your vacant building, the Porta Air team uses a "Rightsizing" approach. In the Chicago area, where winter temperatures often drop below zero, a standard rule of thumb for vacant buildings is to aim for a "maintenance temperature" of 50°F to 55°F to protect the plumbing and fire suppression systems.

Quick Calculation Guide: What Do You Need?

To estimate your needs before calling, you can use the following metrics based on Chicago´s Climate Zone 5:

• · For Maintenance Heat (50-55°F): Multiply your square footage by 25–30 BTUs.
• · For Comfort Heat (68-72°F): Multiply your square footage by 40–60 BTUs (depending on insulation and ceiling height).

Building Size (Sq. Ft.)	Estimated BTUs Needed (Maintenance)	Recommended Electric Unit Size
500 – 1,000	15,000 – 30,000 BTU	10 kW Electric Heater
1,500 – 2,500	45,000 – 75,000 BTU	15 kW – 30 kW Electric Heater
3,000 – 5,000	90,000 – 150,000 BTU	45 kW Electric Heater
10,000+	300,000+ BTU	Fleet of 60 kW – 150 kW Units

500 – 1,000 15,000 – 30,000 BTU 10 kW Electric Heater 1,500 – 2,500 45,000 – 75,000 BTU 15 kW – 30 kW Electric Heater 3,000 – 5,000 90,000 – 150,000 BTU 45 kW Electric Heater 10,000+ 300,000+ BTU Fleet of 60 kW – 150 kW Units

Note: 1 kW of electric heat produces approximately 3,412 BTUs per hour.

Factors That Affect Your Quote

When you call Porta Air for a formal quote, have the following information ready so we can provide the most cost-effective solution:

1. Ceiling Height: A warehouse with 20-foot ceilings requires significantly more "throw" and BTUs than an office with 8-foot ceilings.
2. Available Power: We offer units ranging from 115V (standard plug) to 208V, 240V, and 480V (three-phase). If your building´s power is off, we can also quote a portable generator.
3. Insulation Level: Vacant older buildings with large glass fronts or metal siding lose heat faster and may require supplemental "booster" units near loading docks or entryways.
4. Duration: Are you looking for a weekly "emergency" rental or a monthly "seasonal" rate while the building is listed for sale?

Get Your Custom Quote Today

Don´t guess and risk a burst pipe. Porta Air offers FREE, no-obligation estimates and 24/7 emergency response throughout the Chicago suburbs.

Call us at (888) 519-1422 or visit us online to request a FREE “Spec-Out.” We will help you select the exact combination of electric, direct-fired, or indirect-fired heat to protect your asset all winter long.