Solar for Clinics Uganda — Cold-Chain Sizing Checklist
8 cold-chain questions every clinic solar quote in Uganda must answer. Most quotes count kilowatts, not cold. Here is what they miss.
Quick answer: Solar for a clinic in Uganda must do one thing most quotes never address: keep the vaccine fridge cold through the longest outage your district has seen. A well-built clinic solar system costs UGX 15M–35M depending on load and battery size. But the price is secondary to three things: a dedicated circuit for the fridge, an inverter sized for startup surge (3–5× running amps), and a battery that can carry the fridge through a long grid failure. Without all three, the rest of the quote does not matter.
Most solar quotes for clinics count kilowatts. They forget to count the cold.
If you've been quoted two or three times and nobody asked about your vaccine fridge first — you have not received a clinic solar quote. You've received a home solar quote with a bigger number at the bottom.
You've earned the right to be sceptical.
Solar for clinics in Uganda is not a sizing exercise. It is a continuity guarantee. One load cannot flicker. It cannot wait until morning. A system in a Mukono clinic ran 14 months with no temperature excursion — not because it was expensive, but because three things were done right. The questions below tell you whether your quote does the same.
Print this page. Bring it to the meeting.
A clinic in Mukono — what 14 months of cold-chain continuity looks like
A small private clinic in Mukono. Two consultation rooms, one minor-procedures room, one vaccine fridge. Before solar, every Yaka outage put a 4–8 hour question mark on the cold chain. The clinic ran diesel at UGX 720,000 a month — not by choice, but as insurance against the grid.
We sized to the measured load: fridge, lights, autoclave, three charging points. We wired the fridge on its own output — separate from every other load in the building. The battery cut-off was set so the fridge stays on after the lights switch off. We used a 5 kVA Felicity hybrid with pure sine wave output and a 9.6 kWh LiFePO4 battery.
Fourteen months later: zero unscheduled downtime. The vaccine fridge temperature log is continuous. Not one excursion. The generator started twice — both scheduled load tests. Diesel cost: zero.
One addition not in the original scope: a firmware update at month four, covered under the annual maintenance contract.
That is what a properly designed clinic system looks like. The eight questions below are how you tell whether the quote in front of you delivers the same.
Why clinic solar is not the same as home solar
Any installer can size a home system. Count the appliances, multiply by hours, size the battery. A vaccine fridge breaks that logic in three ways.
Startup surge. A compressor doesn't run at a steady wattage. Each time it cycles on, it draws 3 to 5 times its running current for 2–3 seconds. A WHO PQS-certified fridge running at 150W pulls up to 750W at startup. An inverter sized for running load only will dip on that surge. The dip shows in the temperature log — silently.
The WHO certification covers the fridge — not the system. A WHO PQS-certified fridge is a quality guarantee for the fridge under test. It says nothing about inverter quality, battery depth, or what happens when the grid drops. Those are the installer's job. Most clinic solar quotes in Uganda leave them out.
Critical-load separation. The vaccine fridge needs its own protected output — active even when the main battery reaches cut-off. Without that, the inverter's load decisions affect the fridge. Most home solar templates wire everything to a single output. That is the wrong template for a clinic.
Only 24% of Uganda's health facilities meet adequate cold chain management standards, according to a Makerere University study. The gap isn't power. It is the three things above.
Read the full Uganda solar cost guide, including clinic pricing by load tier →
The 8 cold-chain sizing questions — print this, bring it to the meeting
Read each question to the person quoting your system. If the reply is vague, or silence, or "don't worry about that" — you are not talking to someone who has sized a clinic before.
| # | Question | What you are checking |
|---|---|---|
| 1 | Is the vaccine fridge wired on a dedicated critical-load output? | Without its own output, the fridge shares power with the lights. Any load decision the inverter makes can cut the fridge. |
| 2 | Has the inverter been sized for compressor startup surge — 3 to 5 times the running amps? | A 150W fridge demands up to 750W at startup. An inverter sized only for running load will dip. That dip shows in the temperature log. |
| 3 | Is the battery sized for cold-chain continuity through your district's longest outage — not just an average night? | March–May long rains bring multi-day cloud cover. A battery sized for one night fails on day two. Ask for the sizing calculation in writing. |
| 4 | Is the inverter output pure sine wave? | Modified sine wave causes excess current through the starter capacitor. It shortens compressor life and triggers errors in the control board. Pure sine wave is non-negotiable for vaccine refrigeration. |
| 5 | Is the battery cut-off voltage staged to protect the fridge before the battery runs out? | Most inverters use a single cut-off for all loads. For a clinic, non-critical loads must go first, the fridge last. Ask to see the inverter settings page. |
| 6 | Is there automatic transfer to grid or generator at cut-off? | The fridge cannot wait for a manual generator start at 3am. The transfer switch must be pre-wired, tested, and confirmed in the commissioning report. |
| 7 | Will the commissioning report include a cold-chain test under simulated outage? | This is the only proof that questions 1–6 were done correctly. The engineer cuts grid power; the fridge keeps running; the temperature log is checked. If this test is not in the scope, it didn't happen. |
| 8 | Is there a maintenance contract covering temperature-log review and battery health checks? | A fridge on solar needs quarterly log audits and annual battery checks. Without a contract, the first sign of a problem is a failed vaccine batch — not a warning. |
What a proper commissioning report looks like →
One check you can do today. If you already have a solar system: open the inverter settings and find the battery cut-off voltage. It should be lower for the critical-load output than for the main output. If they are the same — or if there is no critical-load circuit at all — you may already have a cold-chain problem running quietly in your clinic.
Already have a system that's not protecting your cold chain? →
What your quote almost certainly missed
We have reviewed more clinic solar quotes in Uganda than we care to count. Two gaps appear in nearly every one.
Gap one: the surge current calculation. The quote gives you inverter kVA. It does not give you the inverter's peak surge capacity, the fridge's startup current draw, or proof that the first exceeds the second. These are three different numbers. If only one appears in your quote, the sizing hasn't been done. It has been guessed.
Gap two: the commissioning scope. Standard residential work — switch on, check voltage, hand over the manual — is not clinic commissioning. A clinic handover must include a cold-chain test under simulated outage, temperature-log review at 30 and 60 minutes, and a written record that the fridge held 2°C–8°C. Without those three items in writing, you have no proof the system works when it matters.
This is not a criticism of every solar installer in Uganda. It is what happens when a home solar template is used on a clinic.
The standard is different. We don't copy. We design.
The commissioning test you should demand
Before signing any clinic solar handover, ask for one specific test.
Tell the engineer to disconnect grid power. Run the system on battery only. Watch the fridge temperature log for at least four hours.
At four hours, the log must show continuous 2°C–8°C readings. No excursion above 8°C. No drop below 2°C — freezing destroys most live vaccines. No gaps.
If the engineer says this test is not standard — that is the problem. It should be standard. Make it a written condition of your final payment.
We include this in every clinic install we commission. The record goes to the clinic. If a donor or NGO funded the install, it goes to them too.
That documentation is not paperwork. It is proof that the system works when the grid drops at 3am.
See our clinic solar installation page →
Frequently asked questions — solar for clinics, Uganda
What size solar system does a Ugandan clinic need for a vaccine fridge?
A small clinic in Uganda — fridge, lights, autoclave, charging points — typically needs a 5–8 kVA hybrid inverter with a 9.6–15 kWh LiFePO4 battery. The key factor is not total load. It is the inverter's surge capacity versus the compressor startup current, and the battery's ability to carry the fridge through your district's longest outage. A system undersized on either point will run the lights fine and flicker the fridge.
Does a WHO PQS-certified fridge mean the solar system is safe?
No. WHO PQS covers the fridge under test. It says nothing about inverter quality, battery depth, or what happens when the grid fails. Many clinics in Uganda have certified fridges running on modified sine wave inverters or undersized batteries. The cert says the fridge is fit for purpose. It does not say the system is.
What happens if the battery runs out overnight?
If the system has an automatic transfer switch and a generator, the switch happens on its own. If neither is available and the battery hits cut-off before morning — the fridge temperature begins to rise. A staged cut-off voltage buys time. A well-sized battery means this should not happen for any outage your district has seen.
How long do lithium batteries last in a clinic?
LiFePO4 batteries in a well-commissioned clinic system last 10–15 years. Lead-acid in Uganda's heat and daily cycling fails in 18–30 months. We don't use lead-acid for mission-critical loads. The extra cost upfront is the cheapest insurance a clinic can buy.
What does a cold-chain commissioning test cost?
Nothing extra, when scoped correctly. A cold-chain test under simulated outage should be a standard line item in every clinic solar commissioning — not an add-on. If your installer charges separately for it, that tells you how they approach the rest of the job.
Two numbers are all we need.
What is your fridge's running wattage? And what is the longest outage your district has seen in the past year?
Send those two numbers to Eng. Rory on WhatsApp. We will tell you whether the system you've been quoted — or the one you already have — actually protects your cold chain.
No temperature alarm at 3am. No donor call at 6am. Just quiet power.
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