diff --git a/lib/server.js b/lib/server.js
index 7a0d471..207a036 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -2921,7 +2921,9 @@ WalletService.prototype.getTxHistory = function(opts, cb) {
             var level = _.find(levels, {
               level: 'superEconomy'
             });
-            if (level) {
+            if (!level || !level.nbBlocks) {
+              log.debug('Cannot compute super economy fee level from blockchain');
+            } else {
               var minFeePerKb = level.feePerKb;
               _.each(finalTxs, function(tx) {
                 tx.lowFees = tx.feePerKb < minFeePerKb;
diff --git a/test/integration/server.js b/test/integration/server.js
index c372f5c..110dbf0 100644
--- a/test/integration/server.js
+++ b/test/integration/server.js
@@ -6027,7 +6027,6 @@ describe('Wallet service', function() {
           address: mainAddresses[0].address,
           amount: 200,
         }],
-        size: 500,
       }];
       helpers.stubHistory(txs);
       server.getTxHistory({}, function(err, txs) {
@@ -6039,7 +6038,6 @@ describe('Wallet service', function() {
         tx.amount.should.equal(200);
         tx.fees.should.equal(100);
         tx.time.should.equal(20);
-        tx.lowFees.should.be.true;
         done();
       });
     });
@@ -6307,6 +6305,79 @@ describe('Wallet service', function() {
         done();
       });
     });
+    it('should set lowFees atribute for sub-superEconomy level fees', function(done) {
+      helpers.stubFeeLevels({
+        24: 10000,
+      });
+      server._normalizeTxHistory = sinon.stub().returnsArg(0);
+      var txs = [{
+        txid: '1',
+        confirmations: 1,
+        fees: 100,
+        time: 20,
+        inputs: [{
+          address: 'external',
+          amount: 500,
+        }],
+        outputs: [{
+          address: mainAddresses[0].address,
+          amount: 200,
+        }],
+        size: 500,
+      }, {
+        txid: '2',
+        confirmations: 1,
+        fees: 6000,
+        time: 20,
+        inputs: [{
+          address: 'external',
+          amount: 500,
+        }],
+        outputs: [{
+          address: mainAddresses[0].address,
+          amount: 200,
+        }],
+        size: 500,
+      }];
+      helpers.stubHistory(txs);
+      server.getTxHistory({}, function(err, txs) {
+        should.not.exist(err);
+        var tx = txs[0];
+        tx.feePerKb.should.equal(200);
+        tx.lowFees.should.be.true;
+        var tx = txs[1];
+        tx.feePerKb.should.equal(12000);
+        tx.lowFees.should.be.false;
+        done();
+      });
+    });
+    it('should get tx history even if fee levels are unavailable', function(done) {
+      blockchainExplorer.estimateFee = sinon.stub().yields('dummy error');
+      server._normalizeTxHistory = sinon.stub().returnsArg(0);
+      var txs = [{
+        txid: '1',
+        confirmations: 1,
+        fees: 100,
+        time: 20,
+        inputs: [{
+          address: 'external',
+          amount: 500,
+        }],
+        outputs: [{
+          address: mainAddresses[0].address,
+          amount: 200,
+        }],
+        size: 500,
+      }];
+      helpers.stubHistory(txs);
+      server.getTxHistory({}, function(err, txs) {
+        should.not.exist(err);
+        var tx = txs[0];
+        tx.feePerKb.should.equal(200);
+        should.not.exist(tx.lowFees);
+        done();
+      });
+    });
   });
 
   describe('#getTxHistory cache', function() {