About Swellfort Heating & Air Conditioning

Marvin Federico started this company after one specific August call. A homeowner in a 1948 brick rambler off Queens Chapel Road had paid for a new 5-ton condenser eleven months earlier. The house held 72°F on the thermostat and still felt like a basement in July — clammy walls, musty return grille, condensation beading on the supply registers. Three contractors had told her the system was working correctly because it was reaching setpoint. It was reaching setpoint. That was the problem. The unit was two tons oversized for a 1,320 square foot rambler, satisfied the thermostat in seven-minute cycles, and never ran long enough to pull a single pint of water out of the air. Measured indoor relative humidity: 64%. The equipment was new, the installation was clean, and the house was still unlivable — because nobody had run a load calculation. That gap is the reason this company exists.

The Founder — Marvin Federico

Marvin holds Maryland HVACR contractor licensing #01-148326, issued through the Maryland Board of Heating, Ventilation, Air-Conditioning and Refrigeration Contractors, and EPA Section 608 Universal certification #608U-2011-337194 covering R-22, R-410A, and the R-454B systems now shipping under the AIM Act phasedown. He has worked in residential and light-commercial HVAC across Prince George’s County since 2004, founding Swellfort Heating & Air Conditioning in 2015 after eleven years running service and installation crews for contractors along the Route 1 corridor.

His training stack: NATE certification in Air Conditioning Service and Gas Heating Service. ACCA Manual J, S, and D coursework. Continuing education logged annually against the Maryland Building Performance Standards code cycle and the International Mechanical Code as adopted with Maryland amendments. Gas piping work is performed under WSSC Water gasfitter license #GF-72241, since WSSC Water regulates gasfitting separately from state HVACR licensure in both Prince George’s and Montgomery counties.

The discipline shows up in how every visit runs. Measurements before opinions. A dual-run capacitor reading 31 microfarads against a 35 microfarad rating is a different repair than one reading 9 microfarads — both produce the identical symptom of a condenser that hums and won’t start. One is a $180 part. The other usually means the compressor windings have been dragging on a weak start for two seasons. Most contractors quote the second. Marvin quotes what the meter reads.

Why Prince George’s County Breaks Generic HVAC

The Washington suburbs are not the Midwest and are not the Carolinas. Equipment specified from a national template will underperform here for reasons that are physics and building stock, not preference.

76°F Wet Bulb — The Latent Load Problem

The 2021 IECC places Prince George’s County in Climate Zone 4A — mixed-humid. The ASHRAE 1% summer design condition for this part of the Washington metropolitan area runs approximately 93°F dry bulb against a 76°F mean coincident wet bulb. Through July and August, outdoor dew points sit in the low-to-mid 70s for weeks at a stretch. That means a large fraction of the cooling load is latent — moisture that has to be condensed out of the air — not sensible heat.

Latent removal only happens while the evaporator coil is cold and air is moving across it. An oversized condenser satisfies the thermostat on sensible heat in six to eight minutes and shuts down before the coil has reached steady-state dehumidification. The house reads 72°F and feels like 78°F, because relative humidity is sitting at 60–65% instead of the 45–50% the occupants actually want. Dust mites thrive above 50% RH. Mold germinates on the coil and in the return plenum. The correct answer is a Manual J load calculation that separates the sensible and latent components, then Manual S equipment selection targeting a sensible heat ratio near 0.70–0.75 rather than the 0.80+ that most nationally-marketed condensers deliver. Bigger is not better in Zone 4A. Bigger is wetter.

Housing Stock Built Between 1886 and 1965

Hyattsville incorporated in 1886, and the Hyattsville Historic District was added to the National Register of Historic Places in 1982. The building stock across our service area falls into four distinct eras, and each one fails differently:

• Pre-1940 balloon-framed Victorians, foursquares, and Craftsman bungalows — Historic District, Downtown Hyattsville, Mount Rainier, Riverdale Park. No wall cavity suitable for conventional supply ductwork, frequently original hydronic or steam heat, and no return path above the first floor. Retrofit cooling here means ductless multi-zone or small-duct high-velocity, not a conventional split system shoehorned into a closet.
• 1930s–40s subdivision brick — Castle Manor (annexed into Hyattsville in 1945), Queens Chapel Manor, Green Meadows, Avondale Grove. Original gravity-conversion ductwork with undersized returns and panned floor joists that leak conditioned air into crawlspaces.
• Post-war ramblers, Capes, and split-levels, roughly 1946–1965 — Hyattsville Hills, Kirkwood, Knollwood, College Heights, University Hills, Chillum, Adelphi. Second-floor cooling imbalance is nearly universal. Most have a single central return and no dedicated upstairs return path.
• Post-2005 townhomes and mid-rise — Arts District, Riverfront at West Hyattsville, University Town Center. Tight envelopes that need ASHRAE 62.2 mechanical ventilation, and first-generation equipment now aging past warranty.

Failure Modes That Are Specific to This Climate

Three things break here that rarely break in drier markets. Formicary corrosion — microscopic pinhole tunneling through copper evaporator tubing, driven by organic acid vapor combining with moisture and oxygen. It presents as slow refrigerant loss with no visible leak and no oil stain, and it is far more common in humid climates and in tight homes with high VOC loading from new cabinetry and adhesives. Condensate drain biofilm — an air handler in this climate can pull several gallons of water a day out of the air in August. Biological growth in the trap clogs the line, the pan overflows, and the first sign the homeowner gets is a ceiling stain. Every system we service gets a float safety switch. Duct sweating on attic air handlers — a 130°F attic with a 74°F ambient dew point will condense water on any duct run at R-6 or below. R-8 minimum, sealed with mastic rather than cloth tape, is the floor.

Climate Zone 4A Heating Loads and Orphaned Venting

The ASHRAE 99% winter design temperature for this part of the Washington metro runs near 20°F. That is well inside the operating envelope of a modern variable-capacity heat pump, which is why dual-fuel and heat-pump-only conversions make far more sense here than they do in a 5B or 6A climate. The trap is on the venting side. When a chimney-vented 80% AFUE furnace is replaced with a 95%+ condensing unit that vents through PVC out a sidewall, the gas water heater is left alone on an oversized masonry chimney it was never sized for by itself. Draft collapses, flue gas condenses inside the liner, and carbon monoxide spillage becomes a live risk. Correcting that — relining the chimney or converting the water heater — is part of the job, not an upsell. It is also required by the fuel gas venting tables, and it is one of the most commonly skipped steps in this market.

What We Do

Residential and light-commercial HVAC across Prince George’s County, with technical depth in the categories where Zone 4A conditions and pre-war building stock create non-standard demands:

• Air conditioning installation and repair — Manual J load calculation on every replacement, Manual S selection against latent load, R-454B compliant condenser specification, line set sizing, and AHRI certified matched systems rather than mixed coil-and-condenser pairings that void the rating.
• Furnace installation and repair — 80% and 95%+ AFUE single-stage, two-stage, and modulating systems. Combustion analysis on every install. Vent termination and combustion air per the adopted mechanical and fuel gas code, with Washington Gas delivery pressure verified at the appliance.
• Heat pump and dual-fuel systems — sized to the 20°F design temperature, with balance-point calculation and outdoor lockout set from measured load rather than factory default. This is the single strongest efficiency upgrade available in Zone 4A.
• Boiler and hydronic systems — cast iron sectional and modulating-condensing wall-hung units, common throughout the pre-1940 stock in Mount Rainier, the Hyattsville Historic District, Takoma Park, and Riverdale Park where original radiant systems often predate 1940.
• Ductless mini-splits and small-duct high-velocity — the practical answer for balloon-framed homes, converted multi-family, garden apartments, additions, and finished attics and basements where conventional ductwork cannot be routed.
• Indoor air quality — MERV 13 filtration with static pressure verified after the upgrade, whole-home dehumidification for the August latent load, UV-C coil treatment, duct sealing, and ASHRAE 62.2 ventilation for tight post-2005 envelopes.
• Commercial rooftop units and service contracts — for retail along the Route 1 corridor, small offices near Hyattsville Crossing, and light commercial along Route 450 in Bladensburg.

The Service Area

Our Riggs Road office sits in the 20783 corridor between Chillum and Langley Park, a short run from the Capital Beltway, East-West Highway, and Queens Chapel Road. From that base:

• Hyattsville — Historic District, Downtown, Hyattsville Hills, Castle Manor, Queens Chapel Manor, Arts District, West Hyattsville, Kirkwood, Ellaville, University Town Center, College Heights, Knollwood, Clearwood, Avondale, Green Meadows.
• Chillum, Langley Park, and Adelphi — post-war brick ramblers, garden-apartment complexes, and converted multi-family where ductless retrofit and property-manager service contracts are the common need.
• Mount Rainier, Brentwood, North Brentwood, Cottage City, and Colmar Manor — early-twentieth-century foursquares and bungalows with hydronic heat and no existing duct path.
• Riverdale Park, University Park, and Edmonston — 1930s and 40s colonials and Capes, plus floodplain properties along the Northwest Branch and Anacostia where equipment elevation matters.
• Bladensburg and Takoma Park — mixed residential and light commercial, including Montgomery County work in Takoma Park.

How We Work

Measure First

Every replacement quote starts with a room-by-room Manual J, not a rule of thumb and not a match to whatever tonnage happened to be there before. The existing equipment is frequently the source of the problem, and copying its size copies the problem forward. On repairs, we take static pressure, temperature split, superheat and subcooling readings before naming a part. Airflow target is 350–400 CFM per ton at a design external static pressure near 0.5 inches water column. When measured static comes back at 0.9, the answer is duct correction — not a bigger blower and not a new system.

Permits Pulled, Every Time

Mechanical work in Hyattsville and the surrounding municipalities is permitted through the Prince George’s County Department of Permitting, Inspections and Enforcement. Gas piping runs under WSSC Water licensure. Unpermitted equipment swaps are common in this market and they surface at closing, when a buyer’s inspector finds a condensing furnace venting into a chimney or a panel with no disconnect within sight of the condenser. We pull the permit and schedule the inspection on every installation.

Rebates and Credits Applied Before the Quote

Qualifying heat pump and high-efficiency equipment installations may be eligible for EmPOWER Maryland utility incentives through Pepco and for the federal Energy Efficient Home Improvement Credit, which carries an annual cap of up to $2,000 for qualifying heat pumps. We calculate the eligible incentives into the proposal rather than mentioning them after the sale.

Frequently Asked Questions

Who owns Swellfort Heating & Air Conditioning?

Marvin Federico founded and owns Swellfort Heating & Air Conditioning. The company has operated from the Riggs Building on Riggs Road in Hyattsville since 2015, serving residential and light-commercial customers across Prince George’s County under Maryland HVACR contractor license #01-148326. Marvin has worked in the trade across the Washington suburbs since 2004.

Why does my new air conditioner hit 72°F and still feel damp in August?

Almost always oversizing. Prince George’s County sits in Climate Zone 4A with an approximate 76°F design wet bulb, so a large share of the summer cooling load is moisture rather than heat. An oversized condenser satisfies the thermostat on sensible temperature in six to eight minutes and shuts off before the evaporator coil has run long enough to condense meaningful water. The house reads 72°F at 60–65% relative humidity and feels clammy. The fix is a Manual J load calculation with the latent and sensible loads separated, then Manual S selection targeting a sensible heat ratio near 0.70–0.75, and in some cases a supplemental whole-home dehumidifier.

Can you add central air to a pre-1940 Hyattsville home with radiators and no ductwork?

Yes, and there are two viable paths. Ductless multi-zone systems place wall or ceiling cassettes in each conditioned space with only a three-inch line-set penetration per head, which keeps exterior alterations minimal — relevant in the Hyattsville Historic District, listed on the National Register since 1982. Small-duct high-velocity systems route two-inch flexible supply tubing through balloon-framed wall cavities and closet chases, preserving plaster and original trim. Which one fits depends on ceiling heights, attic access, and whether the existing hydronic system is staying in service for heat.

What permits does an HVAC replacement need in Hyattsville?

Mechanical permits for equipment replacement in Hyattsville and the surrounding Prince George’s County municipalities are issued through the county Department of Permitting, Inspections and Enforcement. Any gas piping modification additionally requires a gasfitter licensed through WSSC Water, which regulates gasfitting separately from Maryland state HVACR licensure. Electrical disconnect and circuit work carries its own permit requirement. We pull permits and schedule inspections on every installation, and the permit number appears on your invoice.

R-410A is being phased out. Should I wait to replace my system?

Generally no. Under the AIM Act phasedown, new residential equipment now ships with lower-GWP A2L refrigerants such as R-454B, and R-410A remains legal to service on existing systems — supply will tighten and prices will rise over time, but your current system does not become unserviceable. The real decision is condition-based. If your existing unit is under twelve years old and holding charge, run it. If it is leaking, running R-22, or facing a compressor replacement, the economics almost always favor replacing now with an A2L system rather than putting a major repair into equipment on a shrinking refrigerant supply.

Why does replacing my furnace affect my water heater?

Because they usually share a chimney. Older 80% AFUE furnaces vent through a masonry chimney alongside an atmospheric gas water heater, and the two appliances together produce enough flue volume and heat to maintain draft. Replace the furnace with a 95%+ condensing unit that vents through PVC out a sidewall, and the water heater is left orphaned on a chimney far too large for it alone. Draft weakens, flue gases condense inside the liner and deteriorate the masonry, and carbon monoxide spillage into the house becomes a real risk. The correction is either relining the chimney to the correct diameter or converting the water heater to a direct-vent or power-vent model. We evaluate the venting on every furnace replacement quote, and it is included in the scope rather than discovered afterward.

Contact Swellfort Heating & Air Conditioning — Hyattsville, MD

Our Riggs Road office serves Hyattsville, Chillum, Langley Park, Adelphi, Mount Rainier, Riverdale Park, University Park, Brentwood, North Brentwood, Cottage City, Colmar Manor, Edmonston, Bladensburg, and Takoma Park. Whether the problem is a rambler that cools to setpoint and still feels damp, a Historic District home with radiators and no duct path, or a furnace that needs replacing before the venting gets sorted out, the first step is a measurement, not a guess.

• Owner: Marvin Federico
• Phone: (227) 249-1654
• Address: Riggs Building, 7411 Riggs Rd #224, Hyattsville, MD 20783
• Email: info@swellfortheatingairconditioning.xyz
• Maryland HVACR Contractor License: #01-148326
• EPA Section 608 Universal: #608U-2011-337194
• WSSC Water Gasfitter License: #GF-72241
• General Liability: $2,000,000 aggregate through The Hartford
• Workers’ Compensation: Active through Chesapeake Employers Insurance

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Office Hours

• Monday – Saturday: 9:00 AM – 5:00 PM
• Sunday: Closed