High-Velocity Air Conditioning in Milwaukee: Unico Installation by Burkhardt Heating & Cooling

Your home has good bones. Cast-iron radiators, a solid boiler in the basement, plaster walls with beautiful original detail — and zero ductwork. Every summer, you open the windows and hope for the best, or wrestle with window units that block the light and rattle all night.

You are not alone. Thousands of homes in Whitefish Bay, Shorewood, Wauwatosa, and the East Side of Milwaukee were built decades before central air was even an option. Adding a conventional forced-air system would mean soffits, dropped ceilings, and a gut renovation. That is where high-velocity air conditioning comes in — and it is what Burkhardt Heating, Cooling, Plumbing & Electric has been doing for decades.

Why High-Velocity AC Is Different

Standard central air conditioning relies on large rectangular ducts — typically 8 to 12 inches wide — that need to run through your home's walls and ceilings. In a home built without those pathways, installation means cutting, building soffits, and sacrificing space. It is disruptive, expensive, and often disfiguring to historic interiors.

High-velocity systems use small, flexible supply ducts — just 2 to 2.5 inches in diameter — that can snake through existing wall cavities, up through closets, and across attic floor framing without any of that destruction. The outlets are small round or slotted ports that sit flush in walls, ceilings, or floors. From the living room, they look like a nickel-sized vent. Most homeowners choose covers that match their paint color.

The technical term for this category is Small-Duct High-Velocity (SDHV). Here is what makes it genuinely different from conventional air conditioning:

Aspiration cooling. Because air exits the outlet at high velocity, it draws room air into the stream and mixes it thoroughly. You get even temperature distribution room to room without the hot and cold spots common in larger duct systems.

Superior dehumidification. The Unico system operates at around 200 CFM per ton — about half the airflow of a conventional system. Air moves across a thicker coil with more contact time, pulling out significantly more moisture per pass. This matters a lot in Milwaukee's summer humidity, and especially near the lakefront where East Side homes can see elevated indoor humidity throughout July and August. You can maintain comfort at 74°F instead of cranking the thermostat down to 70°F.

No returns required in every room. Unlike conventional systems, high-velocity systems typically need only one or two central return locations. Less carpentry, fewer penetrations.

Your boiler stays. A high-velocity AC system uses a separate, dedicated air handler for cooling. Your hot-water or steam boiler continues heating the home in winter exactly as it always has. You are not replacing your heating system — you are adding cooling alongside it. Learn more about boiler service and maintenance →

Our Unico-Certified Installation Process

When Burkhardt installs a Unico system, it is not a one-size-fits-all job. Every home is different — different framing, different attic access, different room layouts. Here is what the process looks like:

1. Free in-home assessment. A Burkhardt technician walks your home, measures the conditioned square footage, evaluates attic access and ceiling heights, identifies routing paths for supply tubing, and notes any obstacles. We size the system to the Unico engineering bulletin — not to a rule of thumb.

2. System design and layout. We calculate the number of outlets and tons required for your home (see the sizing guide below). We map the routing paths for the supply plenum and flexible tubing so we know where every outlet will land before a single hole is drilled.

3. Installation. Our crew installs the air handler in a conditioned or semi-conditioned space (a mechanical room, a closet, or an attic when accessible in the right season — more on timing below). We run the fiberglass square plenum and branch out flexible 2-inch supply tubing to each outlet. Outlets are cut into finished surfaces, covers are installed, and the system is commissioned.

4. Start-up and testing. We test airflow at each outlet, verify refrigerant charge, check the S.M.A.R.T. (Software Managed Air Rate Technology) control board settings, and walk you through thermostat operation.

5. Warranty registration. As a Unico Preferred Contractor, we register your installation with Unico within 90 days, extending the standard 5-year parts warranty to a full 10-year limited parts warranty.

We Install Unico — Here's Why

Burkhardt has been installing high-velocity air conditioning systems since the technology came to market. For years, that meant working with both of the major SDHV brands available to contractors.

After installing both SpacePak and Unico for years, we now install Unico exclusively. We have found Unico's air handlers, coils, and control systems offer the durability and long-term reliability our customers expect. We continue to service existing SpacePak systems for homeowners who already have them.

This was not a decision we made lightly or quickly. It came from years of field experience — watching how both systems perform over time, how parts hold up, and how technical support responds when something unexpected happens. Our customers in Whitefish Bay and Shorewood have homes they plan to stay in for decades. The system we install should work that long.

Servicing Existing SpacePak Systems

If you already have a SpacePak high-velocity system in your home, Burkhardt services it. We carry common replacement parts, have technicians trained on SpacePak equipment, and can handle everything from routine maintenance to repairs on existing installations.

If your SpacePak system is aging and you are considering a replacement, we will give you an honest assessment of whether repair or replacement makes more sense for your situation — and if replacement is the right call, we will quote you a Unico installation.

Unico System Sizing Guide

The following sizing reference is drawn from Unico Bulletin 40-010 (official Unico engineering documentation). These are general guidelines; actual sizing requires a Manual J load calculation accounting for insulation levels, window area, ceiling height, and orientation.

Standard design parameters: 6–8 outlets per ton, 250 CFM per ton.

Most homes in Whitefish Bay, Shorewood, and Wauwatosa fall in the 1,500–3,500 sq ft range, typically landing in the 2 to 4 ton range with 14 to 32 outlets.

What Affects Your Project Cost

We do not publish one-size-fits-all pricing for high-velocity AC installation because the range is genuinely wide — and publishing a number that does not apply to your home does not help you.

Factors that affect the cost of a Unico installation include:

• Home size and system tonnage. More square footage means a larger air handler, larger outdoor unit, and more outlets.
• Number of outlets. More outlets mean more material and labor time.
• Routing complexity. An open, accessible attic makes installation faster. A home with tight knee walls, multiple roof pitches, or limited access points takes longer.
• Attic vs. interior installation. Attic installations require timing around temperature (see below). Mechanical room or closet installations can be done year-round.
• Electrical work. The outdoor condensing unit needs a dedicated 240V circuit. If your panel needs an upgrade or a new circuit run, that adds to the project.
• Outdoor unit placement. Standard side-of-house pad installation is straightforward. Rooftop, rear-yard, or constrained locations add complexity.
• Existing refrigerant lines. If this is a replacement install (swapping equipment on an existing Unico system), line set reuse may be possible and can reduce cost.

Burkhardt provides a free in-home assessment. There is no charge for us to walk your home, size the system, map the routing, and give you a written quote. Call us at 414-206-3049 to schedule.

Best Time to Install: Plan Around Peak Summer

If your installation involves running supply tubing through an attic — which is common in two-story Milwaukee homes — timing matters.

Milwaukee attics regularly reach 130°F or higher during July and August. Working in those conditions is dangerous for our crew and can affect the quality of certain installation steps. For that reason, we strongly recommend scheduling new ductwork installations during the shoulder seasons:

• Spring: April and May — Attic temperatures are manageable, and you will have the system ready before the first hot week of June.
• Fall: September and October — Attics cool back down, and you can get ahead of next summer.

Equipment-only swaps — replacing just the indoor air handler or the outdoor condensing unit on an existing system — can be done year-round, since they do not require attic work.

If you are reading this in late June wondering why no one will schedule your installation until fall, this is why. Book early.

Where We Install in Milwaukee

Burkhardt serves Milwaukee, Washington, and Waukesha counties. Within Milwaukee, the bulk of our high-velocity AC work concentrates in the neighborhoods with the highest density of older boiler-heated homes:

Whitefish Bay

Whitefish Bay is home to some of the most architecturally significant residential properties on Milwaukee's North Shore. Homes here — built largely between 1910 and 1940 in Colonial Revival, Tudor, and Craftsman styles — were designed without ductwork and are ideal candidates for high-velocity AC. The proximity to Lake Michigan keeps summer temperatures a few degrees cooler than inland, but interior comfort and humidity control remain important goals.

Shorewood

Shorewood's housing stock spans nearly every decade from the 1880s onward, from modest bungalows to the substantial Lake Drive mansions. Many Shorewood homes remain on original hot-water boiler systems with cast-iron radiators. The village's historic preservation culture means homeowners here are specifically looking for installation approaches that do not compromise original interiors — high-velocity AC is often the only acceptable answer.

Wauwatosa

Wauwatosa's older neighborhoods — particularly the areas around the Menomonee River Parkway and the Village commercial district — contain large numbers of pre-war homes built with steam or hot-water heat. These homes often have generous square footage but limited basement and attic access, which makes routing a more involved design exercise. Our crews are experienced with Tosa's common construction types.

East Side Milwaukee

The Milwaukee East Side — including Downer Avenue, Murray Hill, Prospect Avenue, and the streets surrounding Lake Park — has one of the highest concentrations of pre-war housing stock in the state. Many of these properties are large, multi-story homes where the owners have updated kitchens and baths but have lived with window units for decades. Lakefront proximity also means above-average indoor humidity, making the Unico system's dehumidification performance particularly valuable here.

Our Decades of High-Velocity Experience

Burkhardt Heating, Cooling, Plumbing & Electric has been a family-owned business since 1961. We have been serving Milwaukee-area homeowners through boiler seasons and cooling seasons alike for more than six decades — and we have been installing high-velocity AC systems since the technology first became available to residential contractors.

That history matters for a few reasons. We have seen how these systems age. We know which installation decisions at year one affect performance at year ten. We have installed systems in homes throughout Whitefish Bay, Shorewood, Wauwatosa, and the East Side, which means our technicians are familiar with the specific construction details — the framing patterns, the common attic configurations, the boiler rooms — that make up Milwaukee's historic housing stock.

Our technicians hold NATE (North American Technician Excellence) certification, the industry's leading credential for HVAC service and installation. And as a Unico Preferred Contractor, we have invested in factory training so our team works to Unico's standards, not just general HVAC practice.

Frequently Asked Questions

Will a high-velocity system actually cool a 100-year-old home?

Yes — and it is genuinely the best option for most of them. High-velocity AC was designed specifically for retrofit applications in homes without existing ductwork. The 2-inch flexible supply tubing routes through the same cavities that carry electrical wiring and plumbing. As long as the system is properly sized and the outlets are located correctly, a Unico installation will cool a century-old Milwaukee home just as effectively as any conventional system would cool a newer house.

Can I keep my boiler if I add high-velocity AC?

Absolutely. High-velocity AC installs as an independent cooling-only system alongside your existing heating. Your boiler continues to heat the home through the radiators in winter. You will have separate controls (or a compatible thermostat that handles both), but the heating and cooling systems operate independently. This is one of the primary reasons high-velocity AC appeals to Milwaukee homeowners — there is no reason to abandon a functioning boiler system.

How loud is a Unico system?

When installed correctly, Unico systems are very quiet. The air handler uses an electronically commutated (EC) motor designed for low-noise operation, and the flexible supply tubing has sound-deadening properties built in. The high-velocity outlet sound — a gentle rushing — is typically quieter than the noise from a window air conditioner. That said, noise problems can occur when a system is under-outletted or when sound attenuators are omitted; this is an installation quality issue, not a system flaw. We follow Unico's design specifications, which include proper outlet counts and attenuators where specified.

Will the supply tubing fit in my tight attic or wall cavities?

The 2-inch flexible tubing is designed specifically for retrofit access. It bends, curves, and routes around obstructions that would stop a conventional duct run cold. In most Milwaukee homes — including those with unusually tight framing or complex attic geometry — we have been able to find routing paths. The only homes where routing becomes genuinely constrained are those with extremely limited attic access combined with no viable interior routing alternative. The in-home assessment is where we identify any such constraints upfront.

What does it cost to operate a Unico system?

Operating costs depend on system size, home insulation, thermostat settings, and local electricity rates. The Unico system's superior dehumidification allows many homeowners to set thermostats 2 to 3 degrees higher than they would with a conventional system while maintaining the same comfort level — which directly reduces runtime and energy use. As a general rule, a properly sized and installed Unico system operates comparably to a well-designed conventional system of the same tonnage.

How long will a Unico system last?

Air handler and coil components are designed for 15 to 20 years of service life with regular maintenance. The outdoor condensing unit follows a similar lifespan. The supply tubing, plenum, and outlets have no moving parts and should last the life of the home. As a Unico Preferred Contractor, we register installations for up to a 10-year limited parts warranty — which gives you meaningful coverage through the most common failure window.

What maintenance does a high-velocity system need?

Annual maintenance is the standard recommendation: inspect and clean the evaporator coil, check refrigerant charge, clean or replace the air filter, inspect the condensate drain, and verify the control board settings. Burkhardt offers maintenance agreements that cover both your boiler service and your cooling system service in a single annual visit if preferred. Regular maintenance is also required to keep the Unico warranty valid.

Can I add high-velocity AC in stages — one floor now, one floor later?

It depends on the system design. In some cases, a system can be designed with expansion in mind — a slightly larger air handler and outdoor unit, with additional outlet runs added later. In other cases, adding a second zone or a second floor means a second system. We will give you an honest assessment during the in-home walkthrough, and if phased installation is feasible, we will design for it from the start.

Ready to Cool Your Milwaukee Home Without Wrecking It?

Burkhardt Heating, Cooling, Plumbing & Electric has been the trusted HVAC contractor for Milwaukee's historic neighborhoods since 1961. We are Unico Certified, NATE-certified, and have been installing high-velocity AC longer than most contractors have been in business.

Call us at 414-206-3049 to schedule your free in-home assessment. We will size the system, map the routing, and give you a written quote — no pressure, no obligation.

We serve Milwaukee, Washington, and Waukesha counties, with a focus on the North Shore and East Side neighborhoods where high-velocity AC matters most.