How grid-tied solar and CFE net metering (medición neta) work in Mexico, how to avoid the DAC tariff, realistic system costs, permits, and ROI for foreign property owners.

Mexico has abundant sun and, in many regions, expensive residential electricity once your consumption climbs. That combination makes solar power one of the highest-return upgrades a property owner can make, especially in hot coastal markets where air conditioning drives bills upward. The mechanism that makes it work financially is medición neta, or net metering, run through the national utility CFE.

This guide explains how interconnection works, why avoiding the DAC tariff matters so much, what a system actually costs, and how to think about payback, without the sales-brochure optimism.

Why Electricity Costs Escalate: The DAC Trap

Residential CFE tariffs are tiered and, for lower consumption, partly subsidized. But there is a cliff. If your average consumption over a rolling period exceeds a threshold, CFE reclassifies you into the DAC tariff (Doméstica de Alto Consumo, high-consumption domestic). DAC removes the subsidy, and your per-kWh rate jumps dramatically, often two to three times what a moderate user pays.

For foreign owners running A/C, pool pumps, and appliances in a warm climate, slipping into DAC is common and painful. Once in DAC, you must stay under the threshold for a sustained period to fall back out. This is the single biggest reason solar pays off so well in Mexico: it does not just shave your bill, it can pull you out of, or keep you out of, DAC entirely.

How Net Metering (Medición Neta) Works

Under a small-scale interconnection contract with CFE, you install a grid-tied solar system and a bidirectional meter. The concept:

When your panels produce more than you use, the surplus flows to the grid and you accrue a credit in kWh.
When you use more than you produce (at night, for example), you draw from the grid and consume your banked credits first.
Your bill reflects the net energy, hence medición neta.

Credits typically roll forward within a defined billing cycle. The goal is not usually to sell power for profit; it is to zero out, or nearly zero out, your consumption bill and escape DAC. Systems are commonly sized to match your annual consumption rather than to overproduce, because banked surplus beyond your own use has limited value.

Grid-tied vs off-grid

Grid-tied (interconnected): Uses the CFE grid as your “battery” via net metering. Lower cost, no expensive battery bank, but no power during a grid outage unless you add battery backup.
Off-grid: Fully independent with battery storage. Necessary where there is no reliable grid connection, but significantly more expensive and maintenance-heavy.
Hybrid: Grid-tied plus batteries for outage resilience, a middle path that is popular where outages are frequent.

For most owners with an existing CFE connection, grid-tied net metering delivers the best economics; add batteries only if you specifically need outage protection.

Permits and Interconnection Steps

The process is well established but requires paperwork:

Site assessment and sizing based on your CFE bills and roof/space.
Interconnection application with CFE for a small-scale system, and the appropriate contract.
Bidirectional meter installed or reconfigured by CFE.
Installation by a qualified installer meeting the applicable electrical standards; some jurisdictions require the design signed by a certified professional.
Inspection and commissioning, after which net metering begins.

Confirm that the property’s uso de suelo and any HOA or condo rules permit rooftop solar, and that the electrical service is in your name (or your fideicomiso’s) so the CFE contract aligns with ownership.

What a System Costs

Costs vary by system size, roof complexity, brand, and whether you add batteries. As indicative orientation, not quotes; convert at the day’s exchange rate, rough ranges for a residential grid-tied system:

Small (about 3–4 kW), modest home: roughly USD $3,500–$6,000 (approx. MXN $63,000–$108,000).
Mid-size (about 5–8 kW), typical A/C household: roughly USD $6,000–$12,000 (approx. MXN $108,000–$216,000).
Large (10 kW+), high-consumption or short-term-rental property: USD $12,000–$25,000+ (approx. MXN $216,000–$450,000+).

Adding a battery bank for outage backup can increase the total by USD $3,000–$10,000+ (approx. MXN $54,000–$180,000+) depending on capacity. Again, these are indicative orientation, not quotes; convert at the day’s exchange rate, and you should gather several local quotes.

Return on Investment

ROI hinges on one variable more than any other: which tariff you are on.

If solar keeps you out of, or pulls you out of, DAC, the savings are large and payback is often in the range of three to six years, after which power is essentially free (minus a small fixed charge and maintenance).
If you are a modest, subsidized user well below the DAC threshold, your bill is already low, and payback stretches much longer, sometimes to the point where the investment is about resilience or values rather than pure economics.

To estimate honestly: pull twelve months of CFE bills, identify your tariff and annual kWh, get a system sized to that consumption, and divide net system cost by expected annual savings. Do not accept an installer’s payback figure without seeing the underlying assumptions.

Practical cautions

Size to consumption, not to roof. Overbuilding rarely pays because surplus beyond your use has limited value.
Verify the installer’s track record with CFE interconnections specifically; a botched application delays your meter for months.
Account for maintenance: panels need occasional cleaning (dust, salt air on the coast), and inverters have a finite lifespan.
Salt-air corrosion on coastal properties makes component quality and mounting hardware matter more.

Owner’s Checklist

Pull 12 months of CFE bills; identify your tariff and annual kWh, and whether you are near or in DAC.
Confirm the CFE contract, and the electricity service, are in the correct owner’s name (or fideicomiso).
Check uso de suelo and HOA/condo rules for rooftop solar approval.
Get three local quotes for a grid-tied system sized to your consumption; add batteries only if you need outage backup.
Confirm the installer will handle the CFE interconnection application and bidirectional meter.
Calculate payback yourself using real bills; be skeptical of ROI claims without stated assumptions.
Budget for cleaning and eventual inverter replacement, especially in coastal, salt-air locations.

Key Takeaways

Solar in Mexico is compelling primarily because of net metering (medición neta) and, above all, the punishing DAC tariff it lets you escape. For a high-consumption household running A/C, a grid-tied system sized to your usage can pay for itself in a handful of years and then run nearly free. For a light user already subsidized, the case is softer. Start with your CFE bills, verify your tariff, size honestly, and choose an installer who has done CFE interconnections before. Sun is free; the economics come down to which side of the DAC line you sit on.